Hamas’s handbook for underground combat describes, in meticulous detail, how to navigate in darkness, move stealthily beneath Gaza and fire automatic weapons in confined spaces for maximum lethality.

Battlefield commanders were even instructed to time, down to the second, how long it took their fighters to move between various points underground.

The 2019 manual, which was seized by Israeli forces and reviewed by The New York Times, was part of a yearslong effort by Hamas, well before its Oct. 7 attack and current war with Israel, to build an underground military operation that could withstand prolonged attacks and slow down Israeli ground forces inside the darkened tunnels.

Just a year before attacking Israel, Yahya Sinwar, the leader of Hamas in the Gaza Strip, approved spending $225,000 to install blast doors to protect the militia’s tunnel network from airstrikes and ground assaults.

The approval document said that Hamas brigade commanders had reviewed the tunnels below Gaza and identified critical places underground and at the surface that needed fortification.

The records, along with interviews with experts and Israeli commanders, help explain why, nearly a year into the war, Israel has struggled to achieve its objective of dismantling Hamas.

Israeli officials spent years searching for and dismantling tunnels that Hamas could use to sneak into Israel to launch an attack. But assessing the underground network inside Gaza was not a priority, a senior Israeli official said, because an invasion and full-scale war there seemed unlikely.

All the while, officials now realize, Hamas was girding for just such a confrontation.

Were it not for the tunnels, experts say, Hamas would have stood little chance against the far superior Israeli military.

The underground-combat manual contains instructions on how to camouflage tunnel entrances, locate them with compasses or GPS, enter quickly and move efficiently.

“While moving in the dark inside the tunnel, the fighter needs night-vision goggles equipped with infrared,” the document, written in Arabic, reads. Weapons should be set to automatic and fired from the shoulder. “This type of shooting is effective because the tunnel is narrow, so the shots are aimed at the kill zones in the upper part of the human body.”

Israeli officials knew before the war that Hamas had an extensive tunnel network, but it has proved to be more sophisticated and extensive than they realized.

Early in the war, they estimated that it stretched for about 250 miles. Now they believe it is up to twice as long.

And they continue to discover new tunnels. Just last week, Israeli commandos rescued a Bedouin Arab citizen of Israel who was found alone in an underground warren. The government said on Sunday that six hostages had been found dead in another tunnel.

Mr. Sinwar, Israel’s highest-value target, has been suspected of managing the war and evading capture from a tunnel.

The records show how both sides have had to adapt their tactics in the war. Just as Israel underestimated the tunnels, Hamas prepared for subterranean battles that have not materialized. Israel was reluctant, especially early in the war, to send troops underground where they might face combat. Hamas has primarily ambushed soldiers near tunnel entrances, while avoiding direct confrontations.

That has left Hamas to use the tunnels to launch aboveground hit-and-run attacks, hide from Israeli forces and detonate explosives using remote triggers and hidden cameras, according to Israeli military officials and a review of battlefield photos and videos.

These maneuvers have slowed Israel’s assault, but its military has still decimated Hamas’s ranks, routed them from strongholds and forced them to abandon huge swaths of the tunnel network that they invested so heavily to build.

Members of the Israeli military discovered the tunnel warfare document in Gaza City’s Zeitoun District in November, officials said. A letter from Mr. Sinwar to a military commander was found that same month south of the city. The documents were made available by to The Times by Israeli military officials.

A military spokesperson said that “the fact that Hamas is hiding in tunnels and managing much of the fighting from there prolongs the war.” A senior Hamas official declined to comment on the tunnel strategy.

The markings on the documents are consistent with other Hamas materials that have been made public or been examined by The Times. And Israeli soldiers have described details, like camouflaged tunnel entrances and recently installed blast doors, that are consistent with the Hamas documents. The documents also describe the use of gas detectors and night-vision goggles, equipment that Israeli forces have found inside tunnels.

“Hamas’s combat strategy is based on underground tactics,” said Tamir Hayman, a former head of Israel’s military intelligence. “This is one of the primary reasons they have managed to withstand the I.D.F. thus far.”

Since the war started, much has been revealed about the subterranean network, which has been called the “Gaza Metro.” Hamas uses some rudimentary tunnels simply to mount attacks. The fighting manual describes how people should maneuver these narrow passages in darkness: with one hand on the wall and the other on the fighter in front.

Others tunnels are sophisticated command-and-control centers or arteries connecting underground weapons factories to storage facilities — concealing Hamas’s entire military infrastructure. In some cases, Hamas has used solar panels installed on the roofs of private homes to provide power underground.

Some tunnels also serve as communication hubs. This past winter, Israeli forces discovered a Nokia telecommunications system underneath the headquarters of the U.N. agency for Palestinian refugees.

Such Nokia systems provide voice and data services, according to the manual obtained by The Times, and could have functioned as a switchboard for an underground communication network. But the features require additional hardware and it is not clear what abilities Hamas had.

Hamas has been known to hold Israeli hostages underground, so every tunnel needs to be investigated and cleared, Israeli officials say.

Destroying a tunnel section can take dozens of soldiers about 10 hours, according to a senior Israeli officer who is an expert on tunnel warfare. Last year, the Israeli Army discovered a tunnel that had a depth of 250 feet — about the height of a 25-story building. The army said it took months to destroy it.

“I cannot overstate that in any way. The tunnels impact the pace of the operations,” said Daphné Richemond-Barak, a tunnel warfare expert at Reichman University in Israel. “You can’t advance. You can’t secure the terrain.”

“You’re dealing with two wars,” she added. “One on the surface and one on the subsurface.”

One Israeli special operations officer, who, like others, spoke on the condition of anonymity because they were not authorized to publicly discuss military activities, said that as soldiers approached the tunnels, Hamas sometimes blasted the ceilings, causing cave-ins that would block the path.

An Israeli military official said that it could take years to destroy the entire tunnel network.

Israel’s military leadership has made the tunnels its main target. But the campaign has come at a steep cost for Palestinian civilians. Many of the tunnels snake beneath densely occupied areas. Israel has publicized videos of the military destroying tunnels with more than 16 tons of explosives per kilometer.

The Israeli military estimates that it costs Hamas about $300,000 to build roughly a half-mile-long rudimentary tunnel. Ms. Richemond-Barak said that the letter from Mr. Sinwar highlighted the expense and sophistication behind the effort.

The letter was written to Muhammad Deif, the group’s military commander, who is believed to have been an architect of the Oct. 7 attack. It is not clear when Hamas completed its review of tunnel fortifications or whether it was done in connection to the attack planning. Mr. Sinwar wrote that “the brigades will be given the money according to the level of importance and necessity.”

The letter could indicate where the group anticipated the toughest fighting. Mr. Sinwar authorized the most money for doors in northern Gaza and Khan Younis. Indeed, some of the heaviest fighting during the war has taken place in those areas.

“The Hamas tunnel system was an essential, if not existential element of their original battle plan,” said Ralph F. Goff, a former senior C.I.A. official who served in the Middle East.

It is not clear when Hamas started using the doors, but Ms. Richemond-Barak said the group’s heavy reliance on them was new. She was not aware of Hamas using them during a 2014 war with Israel.

Blast doors seal tunnel segments from each other and from the outside, protecting against bombings and breaches. They also hamper the army’s use of drones to inspect and map tunnels.

The Israeli military has repeatedly encountered blast doors as they cleared tunnels. Despite the tactics described in the tunnel-fighting manual, once those doors have been breached, Israeli officials say, soldiers seldom find Hamas fighters behind them. They have fled, reflecting an attack-and-retreat strategy that has become commonplace.

Eric Schmitt contributed reporting from Washington.

When the Russian invasion of Ukraine began in February 2022 and some of her students fled abroad, Iryna Kovaliova, a literature teacher, decided it was time to retire.

“I wrote my resignation letter and took my things from school,” she said. But the children in her sixth-grade class, 6H, in a Kyiv school, begged her to stay, “at least for the duration of the war,” she recounted in a recent interview.

Two years later, she is still teaching at 63, three years past the retirement age for teachers, torn by the heartbreak of watching her students grapple with the trauma of air raids, bombings and the loss of loved ones. She worries for those who have been displaced, forced to study online, as well as for former students who have already enlisted in the army and are fighting on the front lines.

She begins every morning by checking the social media accounts of two former students who are in the army, relieved when she sees they have been online, knowing that at least they are alive.

Maria Lysenko, the principal of the school, said she was worried for a whole generation of children, but also for her teachers.

“Children are like tuning forks, a reflection of what is happening in our lives,” Ms. Lysenko said. “There is a reason that a child is lying on the desk, maybe he has not slept all night, because he was waiting for news from someone close.”

“But what about the teachers?” she added. “They are holding on, no breakdowns, no panic, doing their best.”

Children and teachers across the country began their first day of classes for the new academic year on Monday at a time when Russia has been stepping up bombardments of Ukrainian cities.

Class 6H is the most troubled group of the sixth grade in Ms. Kovaliova’s school. The children, she says, dislike discipline and cannot sit still after going through lockdown during Covid and then two years of disruption with the outbreak of war.

They often ignore teachers, Ms. Kovaliova said: “It’s a difficult group.”

But, she added, she could see reasons behind their behavior.

“These children are loud. They want to shout something. But we never asked what they are shouting about,” she said.

“These children are crying for help,” she added. “They are like a bleeding wound, and no one sees it.”

So instead of checking their homework on a recent morning, she surprised the class with a sudden question. She invited a reporter from The New York Times along to listen in.

“What changed inside you in these two years?” she asked the class. “And how would you reflect it in a collective painting?”

Since the Russian invasion began, she said she had been pushing the school to consider displaying in the school’s bomb shelter a giant mural, painted by the children, in which they could express their experience of the war. The school prevaricated, so she decided to plunge ahead, asking her students to start thinking about the project.

The first to speak was Danya, 11, a student who was displaced from his home in the Ukrainian city of Luhansk in 2014, when fighting first broke out between Moscow-backed separatists and government forces in the eastern regions of Luhansk and Donetsk.

“Before, I thought of my house as a wardrobe where I could hide, where nothing worries you,” he said. “And it’s not like that.”

Then Yehor, 11, from Kyiv, said he had fled the capital with his mother at the time of the full-scale Russian invasion in February 2022.

“I wanted to stay, but my parents thought that soldiers were already approaching,” he said. “We left. My dad stayed, and he saw with his own eyes a missile flying and hitting.”

Yehor’s family fled to a town west of the capital. He kept a religious icon with him, which he thinks helped them to make the trip safely. He said he wanted to depict that icon on the painting.

Ms. Kovaliova explained her idea: “Imagine, a student comes to the school in 20 years’ time,” she told the class. “The war is over. We live in a happy country. And he sees this mural signed, ‘Class 6-H.’ He sees a wardrobe and an icon on a wardrobe. And he starts thinking.”

“What changed inside you in these two years?” she said. “And how would you reflect it in a collective painting?”

Nazariy, 12, replied, “For me, war is death, in the first place. It’s very painful.”

Nervous laughter broke out in the classroom.

“My uncle died,” he said.

Ms. Kovaliova hushed the class. “How old was he?” she asked.

“Thirty-two,” Nazariy said.

“I want to cry,” Ms. Kovaliova said. “What would you paint?” she asked him.

“A fortress. Knights entering the fortress. And a lot of blood all around,” he said.

“How were you changed?” the teacher asked, turning to the class.

“I became less ashamed to voice my opinion,” Nazar, 12, said. “Before, I was thinking: ‘Damn, why was I born in Ukraine?’ After the war started, I began to feel cool that I’m from Ukraine. I would paint a mirror on the wardrobe — to see how I changed.”

Some of the children spoke about the Ukrainian language.

“Before the war, most people spoke Russian,” said Liudmyla, 11. “And many switched to Ukrainian when the war started.”

“I would paint a lock, meaning our language was locked in a wardrobe, almost not used,” she said. “And now people understand that you need to value it, because it’s your country. It was let out.”

“I was more depressed before the war,” Makar, 11, said. “And I started to speak more Ukrainian. I would draw a shield.”

But war and violence kept crowding in on their thoughts.

“I would draw an ordinary girl in front of the mirror. And in the reflection, a girl in a military helmet,” said Maria, 11, who fled from Donetsk.

Many families have been torn apart as grandparents or other relatives were left behind and ended up on the Russian-controlled side of the front line.

Stories of personal separation and loss began to emerge.

“I didn’t appreciate my relatives, my grandma or great-grandma,” said Maria, 11, who is from the Kyiv region. “I didn’t care about spending time with them. But when my grandma and great-grandma were under occupation, I realized that they could be gone.”

“I would draw a big dome which would protect the whole painting,” she added.

Vira, 12, described running to a bomb shelter on the first day of the war as parts of a missile fell on her neighborhood in Kyiv. “I would draw a missile flying over the dome,” she said.

Liza, 11, said, “I realized I want to live.” She added: “I would draw an angel and a village with half-destroyed houses. Because Russians were in a village where we have a cottage, and now half of the village is destroyed. The angel covers the sky and rebuilds houses from the pieces.”

Arina, 11, revealed that she had been displaced from eastern Ukraine and separated from her grandparents who remained in Russian-occupied territory. She began to weep, and several of her classmates rushed to embrace her.

“I would paint a person crying,” Arina said. “Because people die, and you can’t even visit their grave.”

“It’s a very important conversation,” their teacher said. “Thank you. I understand you better. You understand each other better.”

Stories were tumbling out now.

“My brother died recently, he was 24,” a boy called Sasha said. “I didn’t value those moments of life with him. I would paint arms holding coffins.”

“Our painting is getting complicated,” he added.

Another classmate, Kyryl, spoke up.

“When the war began, it was much scarier than I expected,” he said. “I would paint fear.”

“How would you paint fear?” Ms. Kovaliova asked him.

“Darkness,” Kyryl replied.

Russia carried out its third large-scale bombardment of Ukraine in a week on Monday, with explosions ringing out early in the morning in Kyiv and several other cities after a volley of missiles was fired on the first day of the school year.

The attacks extended Russia’s terrorizing assaults on cities across Ukraine that began a week ago, even as it pushes forward with fierce attacks along the frontline in Ukraine’s East.

Ukraine has responded by launching drones at refineries and electrical plants in Russia, including one near Moscow on Sunday, causing fires and other damage. The Monday attack came around 5:30 a.m., after a countrywide air alert, and after a missile the night before had struck an orphanage in the northeastern city of Sumy, wounding two children and 11 adults, according to the city council and Ukraine’s public broadcaster, Suspilne.

The attack stood out for the number of ballistic missiles fired at Kyiv, said Serhiy Popko, the military administrator in Kyiv, but early reports suggested that casualties and damage were minor.

The Air Force said it had shot down nine ballistic missile but did not specify where, and that in total Russia had fired 58 missiles and one-way attack drones. Ballistic missiles pose a greater risk of breaking through air defenses as they fly much faster than cruise missiles.

The Russian attack prompted Poland, a member of the North Atlantic Treaty Organization, to scramble fighter jets along its southeastern border, but there were no reports of missiles crossing into Polish airspace.

The bombardment came amid a rising tempo in the war on the ground and in the air. Near the threatened eastern Ukrainian city of Pokrovsk, Russian troops attacked 63 times in the past 24 hours, Ukraine’s general staff said. In the air, Ukraine lost a prized Western-supplied F-16 fighter jet — one of only a half-dozen or so they possess — in a crash a week ago, amid the swirl of a major Russian drone and missile attacks.

Just hours after the explosions, children in Ukraine began returning to classes. In cities near the front, nearly all education takes place online, but many schools are open in Kyiv.

“My first fear was that Russians may target the educational institutions because it’s the beginning of the school year,” said Anna Pantyukhova, a mother of two boys, who are 11 and 14. The family waited out the air raid and “when it was over, I quickly got them ready, and they were glad to be going back to school,” she said.

Nikita Deyev, 13 and in the ninth grade, said he spent the early morning in a bomb shelter, then got ready for school. “I had no doubt I would go, even though there were strikes in the morning,” he said.

Schools in Ukraine must provide bomb shelters for students or operate only online, under a law that came into force after Russia invaded the country in 2022.

Last year, only about half of Ukrainian school children had access to in-person education, with the remainder displaced by the war or enrolled at schools without bomb shelters.

Teachers escort children to the shelter, often the basement of a school, during air alerts. If an alert is in effect at the start of the school day, parents are asked to wait until it is over before dropping off their children.

On Monday, the authorities announced an all-clear around 6:30 a.m., allowing schools to open nationwide for the first day of the school year, when children traditionally wear embroidered shirts and bring flowers for their teachers.

Mr. Popko, the military administrator, said that in addition to the ballistic missiles fired at Kyiv, Russia had fired more than 10 cruise missiles.

The cruise missiles, which are slower than ballistic missiles but can change direction during flight, maneuvered for about two hours before setting a course toward Kyiv, arriving simultaneously with the ballistic missiles, he said in a post on social media.

Debris from intercepts by antiaircraft missiles over the city fell in four districts, setting four cars on fire and damaging commercial buildings, Kyiv’s mayor, Vitali Klitschko, said in a statement. Mr. Klitschko wrote that two people had been wounded.

The authorities also reported explosions in Kharkiv, not far from the Russian border in northeast Ukraine, following bombardments there on Friday and Sunday.

The regional prosecutors said Monday that they had recovered wreckage of a type of North Korean missile, a Hwasong-11, from the site of one early morning strike in the city. The office said the identification was preliminary, based on an early examination of debris. The Ukrainian authorities have earlier reported finding debris from North Korean-made missiles in the city.

Before the attack on Monday, President Volodymyr Zelensky of Ukraine said that over the previous week Russia had fired more than 160 missiles of various types, 780 guided aerial bombs and 400 attack drones at Ukrainian targets.

Ukrainian officials have appealed to allies to allow the use of long-range weapons provided by the West, such as rockets and cruise missiles, to strike back at targets in Russia.

Ukraine’s military is stepping up strikes with domestically produced drones. On Sunday, Russia’s military claimed to have thwarted a major Ukrainian drone attack, but fires at refineries and power plants suggested that at least some had gotten through.

Maria Varenikova, Natalia Novosyolova and Anna Lukinova contributed reporting from Kyiv.

The far-right Alternative for Germany, or AfD, had a very successful night in two East German states on Sunday, with nearly a third of voters voting for the party, whose state chapters have been classified as “confirmed extremist” by German domestic intelligence.

But while a far-right party doing so well in two German states less than eight decades after the end of Nazi Germany is symbolically fraught, it will likely have only limited impact on Germany’s national politics. Although a record number of voters turned out on Sunday in the two states, only about 7 percent of all Germans were eligible to vote.

Nor is the AfD expected to find allies easily. All the other parties that won statehouse seats on Sunday have committed themselves to not collaborating with the far right, in a strategy that will further alienate far-right voters but that is intended to ensure democratic stability in government.

Still, the elections will have ripple effects that are hard to predict, not least on the success of a far-left party that did not exist last year. In Thuringia, the smaller of the two states, nearly half of the voters chose extremist parties, which will force parties to make difficult compromises in the coming weeks if their leaders are to create a stable, working government.

In Saxony, where the mainstream Christian Democratic Union, or C.D.U., came in first, things are slightly more straightforward, in part because Greens and Social Democrats could retain a role in a minority government.

Here are some takeaways from the election:

The far right is surging in the former communist east.

With nearly 33 percent of the vote in Thuringia and 31 percent in Saxony, the AfD had its best statewide showing since it was founded as a euroskeptic party 11 years ago.

The AfD’s first-place finish in Thuringia could make governing the state messy. Björn Höcke, the AfD’s state leader, announced on Sunday that as the largest party, the AfD would be looking for coalition partners — what will probably be a futile, if time-consuming stunt.

But more important, AfD has probably won enough seats in Thuringia’s statehouse to block certain critical votes that require the assent of two-thirds of legislators, including to change the state’s Constitution.

While the AfD has done well in eastern states, it tends not to in the west of Germany. In the European Union’s parliamentary election this June, the party got 15.9 percent of the vote across the country.

Still, the surge in the AfD could help push mainstream parties to adopt positions associated with the far right, and many politicians have already shifted on some issues, including rules on deportations.

A far-left party emerged as a new force.

The upstart Sahra Wagenknecht Alliance, known by its German initials B.S.W., had a historic night.

The party, which was not founded until January, garnered nearly 16 percent of the vote in Thuringia and almost 12 percent in Saxony. Those results, coupled with the fact that no one is willing to work with the AfD, mean it will likely play a part in one or both state governments — which is unheard-of for a party that is less than a year old.

Sahra Wagenknecht, the former communist who founded the party, has said that she would not join a coalition with parties that support arming Ukraine. It remains to be seen to what extent she insists on that stance, which is one of her party’s main planks, or whether the C.D.U., which has consistently pushed Chancellor Olaf Scholz to help Ukraine and is hoping to run both state governments, will change its course on the issue.

In either case, Sunday’s elections could help temper Germany’s willingness to support Ukraine militarily.

Scholz’s coalition was weakened further.

Although Mr. Scholz’s Social Democratic Party garnered enough voter support on Sunday to remain in both statehouses, the same could not be said of his two governing partners. With less than the 5 percent needed to sit in the statehouse, the Greens and the Free Democratic Party, or F.D.P., were both kicked out of the state parliament in Thuringia. The F.D.P. also failed to win enough seats to enter Saxony’s state parliament.

While the results of the election don’t immediately affect the coalition, it could drive some members to reconsider sticking with it until the next federal election a year from now.

But even if the coalition does hold, the election results are expected to stymie new progressive laws, as coalition partners become ever more nervous about a right-wing backlash in next year’s election.

A viable mainstream opposition still exists.

The only mainstream party to come out on top on Sunday was the C.D.U., which has been in the opposition in Berlin since Angela Merkel, its longtime leader, did not run again for chancellor in 2021.

The results on Sunday will likely benefit Friedrich Merz, the C.D.U.’s leader. Analysts said the results suggest that, under his more conservative leadership on issues like immigration, the party has a chance against populist rivals.

And while there are weeks to go before the states form governments, it is likely that both Thuringia and Saxony will be lead by a C.D.U. governor, which would give the party added power in Berlin through the Federal Council of States, which comprises state leaders.

“We are the bulwark,” Carsten Linnemann, the C.D.U. secretary general, told reporters on Sunday.

Pope Francis leaves Monday on an 11-day trip to Southeast Asia and Oceania, the longest and among the most complicated of his tenure. It could be particularly challenging for Francis, 87, who has been using a wheelchair and battling health problems.

But the trip, which includes a stop in Indonesia — the world’s largest Muslim majority country — also signals he has no intention of slowing down his outreach to faraway Catholics.

Francis will visit four countries for a total of about 20,000 miles by plane. From Indonesia he goes to Papua New Guinea, then East Timor and Singapore, as he deepens his engagement with Asia, one of his priorities.

The trip will include more than 43 hours of air travel and meetings with local faithful, clergy and politicians in cities with tropical climates or high levels of pollution on the other side of the world from Rome.

“It’s a physical test,” said Massimo Faggioli, a professor of theology at Villanova University, “and a sign that this pontificate is far from being over.”

Why is he visiting these countries?

The pope chose four island nations as he extends his outreach to what he calls “the peripheries,” a term for overlooked, faraway places with small, minority or persecuted Catholic communities. The trip is also one of Francis’ boldest engagements with Asia, a fast-growing part of the world, which the pope has always regarded as a strategic objective.

Francis made a largely secretive deal with China in 2018 for the appointment of bishops, but not all issues have been resolved, as China’s government still exerts strong political control over religious life, said Gianni Criveller, dean of studies at the PIME International Missionary School of Theology in Milan.

While no pope has been able to visit China, Francis has taken trips, such as to Mongolia, that have basically put him on China’s doorstep. This time as well, Mr. Faggioli said, the trip is seen as an attempt to “talk to countries he can’t go to.”

He said the trip also showed Francis’ ambition to make the Roman Catholic Church truly global — drawing attention to areas not traditionally of Christian culture and where Catholicism coexists with other religions, relying on the communities’ devotion rather than on wealth, endowments or a historical hegemony.

Unlike in Europe, the Catholic church in Asia does not “rest on its laurels,” said Mr. Faggioli, and believing is in some cases still an act of resistance.

“He sends a message to all the Catholics,” Mr. Faggioli said. “That the future of the church looks more like these churches in which we are a minority than those in which we are a majority.”

The pope’s first stop, Indonesia, also reflects Francis’ commitment to promoting dialogue between Muslims and Christians. He was the first pope to visit the Arabian Peninsula, in 2019.

He is also likely to urge global action to protect the environment, in a part of the world that is particularly vulnerable to climate change, including rising sea levels and severe weather events like droughts and typhoons.

Is the pope too frail for such a trip?

The Vatican originally had considered the trip for 2020 but canceled it because of the pandemic. Despite being older now, the pope is committed to showing that despite his age and ailments he is “still alive though some wanted me dead,” as he once joked.

In recent years, Francis’ health has been a source of concern. Within three years, he underwent a hernia operation, had colon surgery and was hospitalized for a respiratory infection. Last year, he did not attend a summit in Dubai because of health problems.

Still, the pope has been seen walking in recent weeks, instead of using a wheelchair, as he has increasingly done.

In the 11-day trip, he will be accompanied by his medical team (two nurses and a doctor) and, in a first, by his secretaries. Matteo Bruni, the Vatican’s spokesman, said at a news briefing on Friday that no extra precautions were taken for this trip, as the measures they normally adopt were considered sufficient.

Still, the ambitious itinerary for the octogenarian leader of the world’s Roman Catholics inevitably has stirred questions about the impact on his health.

Reporters questioned Mr. Bruni about the 92 percent humidity that the pope would face in Vanimo, a town tucked between Papua New Guinea’s rainforest and the Pacific Ocean. Markus Solo, an Indonesian priest who focuses on interfaith dialogue at the Vatican, said he worried about the impact that Jakarta’s high pollution could have, partly because Francis lost part of a lung to infection as a teenager.

“Hopefully, the government will do something in order to reduce the pollution during the visit,” he said.

The head of the Environmental Service of Jakarta, Asep Kuswanto, said no specific plans for curbing air pollution had been made for the pope’s visit.

Still, it appeared that some measures had been taken to protect the pope’s health. Francis was not expected to visit Flores, a predominantly Catholic Indonesian island.

“His health condition doesn’t permit him to go all that way,” said Father Solo, originally from Flores. “We have to be very prudent.”

Ismail Cawidu, a senior official at Istiqlal Mosque in Jakarta, an important stop on the visit, said that the pope would not tour the inside of the mosque but instead meet other religious leaders at a plaza outside.

Mr. Ismail said they had asked the Vatican if the pope could cross the “tunnel of friendship” that connects the mosque, Southeast Asia’s largest, with a Catholic cathedral but were still awaiting a response.

What can we expect from the trip?

• Indonesia has a large Christian population, with a lively Catholic community. The country has been considered an example of interfaith tolerance but is still facing challenges to its image, as extremist Islamic groups have exerted growing pressure on other religions.

  The pope’s visit to the Istiqlal mosque will include a meeting with representatives of the country’s officially recognized religions — Islam, Buddhism, Confucianism, Hinduism and Catholic and Protestant Christianity. He will also celebrate Mass at a stadium in the city, where tens of thousands are likely to attend.

• Papua New Guinea, where more than 800 languages are spoken, is one of the world’s poorest countries, and Pope Francis “wants to send a message that he can reach everyone, that nobody is too faraway,” Father Criveller said. After spending most of next weekend in Port Moresby, the capital, Francis will fly north to the coastal town of Vanimo, and he may address the issue of protecting nature from extractive businesses and the effects of climate change.

• In East Timor, Asia’s newest nation and the only predominantly Catholic country on the trip, Francis is to follow in the footsteps of John Paul II, who also visited the conflict-scarred nation. Francis may face questions over the scandal involving Carlos Ximenes Belo, a Nobel-winning bishop and independence hero who the Vatican acknowledged had sexually abused young boys.

• In Singapore, an economic powerhouse with a blend of Asian ethnicities and religions, Francis will witness one of the world’s most diverse societies up close, as well as a small but dynamic Catholic community, where the faithful still crowd pews.

The helicopter crash that killed Iran’s president in May was mainly caused by bad weather, including dense fog, Iranian state media reported, citing the conclusions of a final investigation report.

The president, Ebrahim Raisi, was a hard-line religious cleric and a protégé of Iran’s supreme leader, Ayatollah Ali Khamenei. His death shook Iran at a strained moment for the country — facing a volatile conflict with Israel, economic struggles at home, and complex diplomacy over its nuclear program.

The state news agency, IRNA, had reported in June that “technical failure” had contributed to the crash. But on Sunday, it said the final report from an investigation by Iran’s armed forces had determined that “the accident was primarily caused by weather conditions, including thick fog.”

The investigation found that “all major repairs and replacement of critical parts” for the helicopter had been “carried out in accordance with standard regulations,” IRNA reported, and the debris showed “no defects” that could have contributed to the crash. IRNA added that the report found “no signs of sabotage or tampering.”

On the day of the crash, the president, along with the influential foreign minister, Hossein Amir Abdollahian, and other officials, had been returning in a convoy of three helicopters from an event in Azerbaijan.

Shortly after takeoff, around 1 p.m., the helicopters flew into a heavy fog in a region of mountains and valleys, not far from Iran’s northern border.

When the lead helicopter emerged from the fog, the people onboard realized that they had lost track of the president’s helicopter behind them, and that it was not responding to radio calls, Mehrdad Bazrpash, the minister of transportation, later told state television.

The disappearance of the president’s helicopter set off a frenzied, difficult search through rain, fog and forests. There were no survivors at the crash site when the wreckage was found.

The helicopter had exploded on impact, Iran’s Armed Forces said in a statement, later adding that a preliminary investigation showed no signs of foul play or bullets on the aircraft. Some officials questioned whether security protocols were observed and why the president traveled by helicopter into bad weather conditions.

In addition to the president and the foreign minister, the helicopter was also carrying Ayatollah Mohammad-Ali Al-Hashem, who was an imam in the northern city of Tabriz; Malek Rahmati, the governor of East Azerbaijan Province; and Gen. Seyed Mehdi Mousavi of the Ansar unit of the Revolutionary Guards Corps, Iran’s equivalent of the Secret Service, who was the chief of presidential security.

While some Iranians mourned Mr. Raisi, others welcomed the loss of a man they viewed as a central figure in a corrupt regime who oversaw the execution of dissidents, used violence to suppress and kill protesters, and arrested journalists and activists.

The death of Mr. Raisi, 63, prompted a special election that was won by a reformist candidate who advocated moderate policies at home and improved relations with the West.

For years, she had been losing hair and weight. She had started forgetting whole days, and sometimes appeared to be in dreamlike trances. Her children and friends worried she had Alzheimer’s.

But in late 2020, after she was summoned to a police station in southern France, she learned a far more shattering story.

Her husband of 50 years, Dominique Pelicot, had been crushing sleeping pills into her food and drink to put her into a deep sleep, the police said, and then raping her. He had ushered dozens of men into her home to film them raping her, too, they said, in abuse that lasted nearly a decade.

Using the man’s photographs, videos and online messages, the police spent the next two years identifying and charging those other suspects.

On Monday, 51 men, including Mr. Pelicot, went on trial in Avignon, in a case that has shocked France and cast a spotlight on the use of drugs to commit sexual abuse and the broader culture in which such crimes could occur.

The accused men represent a kaleidoscope of working-class and middle-class French society: truck drivers, soldiers, carpenters and trade workers, a prison guard, a nurse, an I.T. expert working for a bank, a local journalist. They range in age from 26 to 74. Many have children and are in relationships.

Most are charged with raping the woman once. A handful are accused of returning as many as six times to rape her.

The victim, who has divorced her husband and changed her surname since his arrest, is now in her 70s.

Since his arrest, Mr. Pelicot, 71, has “always declared himself guilty,” said Béatrice Zavarro, his lawyer. “He is not at all contesting his role.”

Other defendants have denied the rape charges, with some arguing that they had the husband’s permission and thought that was sufficient, while others claimed they believed the victim had agreed to be drugged.

When the police showed the victim some of the photographs they say her husband had carefully classified and stored, she expressed deep shock. She and her husband had been together since they were 18. She had described him to the police as caring and considerate.

She had no memory of being raped, by him or the other men, only one of whom she recognized, she told the police, as a neighbor in town.

The first time she will consciously witness the rapes, her lawyer Antoine Camus says, will be in the courtroom when the video recordings are played as evidence.

The trial comes at a moment of heightened scrutiny of the handling of sexual crimes in the country. Rape is defined in French law as an “act of sexual penetration” committed “by violence, coercion, threat or surprise.” A number of feminist lawmakers want to amend that wording to say explicitly that sex without consent is rape, that consent can be withdrawn at any time, and that consent cannot exist if sexual assault is committed “by abusing a state impairing the judgment of another.”

“There is a kind of naïveté on the topic of predators in France, a kind of denial,” said Sandrine Josso, a lawmaker who led a parliamentary commission into what is known in France as “chemical submission” — drugging someone with malicious intent. She started the commission after she says she became the victim of a drugging last year. A senator is being investigated on accusations that he slipped ecstasy into her Champagne.

Ms. Josso hopes that the Avignon trial will draw attention to the use of drugs to prey on women, and also shed light on the wide profile of predators. “They could be your neighbors, without falling into paranoia,” she said.

Mr. Pelicot seemed like a classic man next door. He was a trained electrician, an entrepreneur and an avid cyclist. His middle child and only daughter, Caroline Darian, her pen name, described him as a warm and present father in a book published in 2022 about the case, “And I Stopped Calling You Papa.” She tried to turn her family trauma into action, forming a nonprofit association, “Don’t Put Me to Sleep,” to publicize the dangers of drug-facilitated crimes.

Her father, she wrote, was the one who drove her to school, picked her up late from parties, encouraged her and consoled her. Her mother was the stable breadwinner, working as a manager in a Paris-area company for 20 years.

When she retired, they moved to a house with a big garden and pool in Mazan, a small town northeast of Avignon. The couple regularly hosted their three children and grandchildren for summer vacations peppered with late dinners on the terrace, where the family debated, held dance competitions and played Trivial Pursuit.

“I think of us as happy,” his daughter wrote. “I thought my parents were.”

None of them harbored any suspicions. Then, in 2020, three women reported Mr. Pelicot to the police for trying to use his camera to film up their skirts in a grocery store, and he was arrested.

The police seized his two cellphones, two cameras and his electronic devices, including his laptop, before releasing him on bail.

On the devices, the police say they found 300 photographs and a video of an unconscious woman being sexually assaulted by many people. They said they also found Skype messages in which the man boasted of drugging his wife and invited men to join him in having sex with her while she was unconscious.

Over the course of their investigation, the police found more than 20,000 videos and photographs, many of them dated and labeled, in an electronic folder titled “abuse.” The timeline they built began in 2011. The list of suspects grew to 83.

Two months after his initial arrest, Mr. Pelicot was arrested again and charged with aggravated rape, drugging and a list of sexual abuse charges. He is also accused of violating the privacy of his wife, daughter and two daughters-in-law on suspicion of illegally recording, and at times distributing, intimate photos of them.

If he is found guilty, he faces up to 20 years in prison.

During interviews with the police, the details of which were included in an overview of the case by the investigative judge, Mr. Pelicot said he began drugging his wife so he could do things to her, and dress her in things, that she normally refused. Then he started inviting others to participate. He said he never asked for or accepted money.

He met most of the men, the investigating judge’s report stated, in a chat room on a notorious, unmoderated French website implicated in more than 23,000 police cases in France alone from 2021 to 2024. It was finally shut down, and its owner arrested, in June after an 18-month investigation stretching across Europe.

The chat room where most of the men met Mr. Pelicot was called “a son insu,” which means “without their knowledge.”

Over the years, Mr. Pelicot told the police, he developed rules for the visitors to ensure that his wife did not wake: no smoking or cologne; undress in the kitchen; warm hands under hot water or on a radiator, so their cold touch would not jolt her. At the end of each night, according to the investigating judge’s report, he cleaned his wife’s body.

Of the 83 suspects, the police identified and charged 50.

Only one of the men is not charged with rape, assault or attempted rape of Mr. Pelicot’s wife. Instead, that man is accused of following the same model, and drugging his own wife to rape her. Mr. Pelicot is also charged with raping the man’s wife while she was drugged.

Five of the men also face charges for possessing child sexual abuse imagery.

Mr. Pelicot is also being investigated in the rape and murder of a 23-year-old woman in 1991 and the attempted rape of a 19-year-old in 1999. He admitted to the attempted rape, according to Florence Rault, the lawyer representing the victims in both cases, but denies any involvement in the 1991 homicide.

The story has prompted some soul-searching among doctors, since Mr. Pelicot’s wife had visited gynecologists and neurologists over a series of mystifying symptoms, but had received no diagnosis, according to her daughter.

“What I found disturbing for us doctors was that no doctor considered this hypothesis,” said Dr. Ghada Hatem-Gantzer, a well known obstetrician-gynecologist and expert in violence against women. She and a pharmacist, Leila Chaouachi, have now developed training for doctors and nurses on the symptoms that victims of drug-facilitated assault can experience.

Contrary to popular belief, most cases occur at home, not at bars, said Ms. Chaouachi, who runs annual surveys on such offenses in France. Most victims are women, the surveys show, and around half of the victims do not remember the attack, because of blackouts, she said.

In the case going to court in Avignon, some of the accused admitted guilt to the police. According to the investigating judge’s report, many claimed that they were tricked into having sex with a drugged woman — lured by a husband for a three-way encounter and told she was pretending to sleep, because she was shy.

Several said they believed that she had consented to being drugged and raped as part of a sex fantasy. Some said they did not believe it was rape, because her husband was there and they believed he could consent for both of them.

“It sends shivers down the spine regarding the state of affairs in French society,” said Mr. Camus, who is also representing Ms. Darian and many other members of the family. “If that’s the conception of consent in sexual matters in 2024, then we have a lot, a lot, a lot of work to do.”