PUBLISHED November 29, 2019

“He put a camera in a carcass and waited for the wolves to come.”

That, says Whitney Johnson, director of visuals and immersive experiences, is the kind of effort that makes for a standout National Geographic photo.

How does she choose 100 photos from 106 photographers, 121 stories, and more than two million images taken over the course of a year?

“I count on my great photo editors,” says Johnson.

One of her favorite images is the lead photo of the “Mona Lisa” because it reflects what Johnson calls “the magic of what makes photography hard—showing something familiar in a new way.” It also speaks to what happens behind the scenes—the photo editor getting access while the museum was closed—and behind the lens, that charmed combination of luck, accident, and a “photographer really seeing the moment.”

With California’s Yosemite Valley far beneath him, Alex Honnold free solos—which means climbing without ropes or safety gear—up a crack on the 3,000-foot southwest face of El Capitan. Before he accomplished the feat on June 3, 2017, Honnold spent nearly a decade thinking about the climb and more than a year and a half planning and training for it. Photograph by Jimmy Chin

Time is reflected in other ways too. There’s the frozen body of Susan Potter, a woman determined to donate her body to medical education, a story carefully shepherded for 17 years by photo editor Kurt Mutchler. And there’s the heartbreaking photo of Sudan, the last male northern white rhinoceros, as he lay dying.

The image that speaks most to me is that of an orphaned young giraffe, its long neck draped over its human caregiver in what looks to be a loving hug. The giraffe now runs free with a wild herd. When exploring these pictures, we all might hear from our own internal photo editor, the voice inside us that tells us to pause, asking us to take a closer look.

An orphaned giraffe nuzzles a caregiver at Sarara Camp in northern Kenya. Samburu cattle herders found the abandoned calf and alerted Sarara—known for raising orphaned mammals and returning them to their habitat. The young giraffe now lives with a wild herd. Photograph by Ami Vitale

Petronella Chigumbura, a member of the Akashinga—a nonprofit, all-female anti-poaching unit—practices reconnaissance techniques in the Zimbabwean bush. Photograph by Brent Stirton

A male elephant grabs an evening snack in Mozambique’s Gorongosa National Park. Most of the park’s elephants were killed for their ivory, used to buy weapons during the nation’s 15-year civil war, which ended in 1992. With poaching controlled, the population is recovering. Photograph by Charlie Hamilton James

Issa Diakite, 50, built both his barbell and his home, one of dozens of chabolas clustered near an Andalusian agricultural region in Spain. Originally from Mali, he settled in as a regular fieldworker and now helps other migrants build shacks. Photograph by Aitor Lara

Cynthia Ikirezi (center) beams with her fellow prefects, student leaders, at Gashora Girls Academy in Rwanda. Educating girls and preparing them for leadership roles are government priorities to empower women. Photographs by Yagazie Emezi

Marines have to be able to carry one another if necessary. USMC Cpl. Gabrielle Green hefts a fellow marine as they ready for deployment on a Navy ship at Camp Lejeune, North Carolina. Of the 38,000 recruits who enter the corps each year, about 3,500 are women—or, in USMC phrasing, “female marines.” Photograph by Lynsey Addario

Encased in polyvinyl alcohol, Susan Potter’s body awaits freezing after she donated her body to science. It was frozen, sawed into four blocks, sliced 27,000 times, and photographed after each cut. The result: a virtual cadaver that will speak to medical students from the grave. Photograph by Lynn Johnson

Canadian soldiers climb on the wreckage of a plane, roughly a thousand miles south of the North Pole, to scout the area during an Arctic survival course on Cornwallis Island. As the Arctic warms and tensions over its future rise, the Canadian and U.S. militaries have stepped up operations in the region. Photograph by Louie Palu

Some 400 U.S. soldiers practice parachute jumps near Alaska’s Fort Greely. The multinational exercise, which includes Canadian forces, prepares troops for the rigors of large, coordinated operations in extreme cold conditions. Photograph by Louie Palu

Canadian soldiers build an igloo during the high Arctic phase of their training to become Arctic operations advisers. In this part of the program, they learn to travel, survive, and build shelters when they reach the high Arctic. Photograph by Louie Palu

Buyers choose animals at the livestock market and send them to this slaughterhouse in Agadez, Niger, where camels, goats, sheep, and other animals are killed and then sent to butchers who sell the meat. Photograph by Pascal Maitre

In Agadez, Niger, an Izala school educates about 1,300 students. Izala is a back-to-basics Islamic reformist movement that adheres to conservative practices, such as women covering their faces, but also prizes education. Photograph by Pascal Maitre

A teenager is dusted with sand from toiling in a mine. He is one of many Nigeriens who joined the rush for gold in the north, the last hope for jobless men after tourism plunged, uranium mining declined, and a law made transporting migrants a crime. Photograph by Pascal Maitre

Stuck in the desert beyond Agadez, Niger, after their truck broke down, these migrants who are hoping to make it to Libya burn a tire to keep warm. Photograph by Pascal Maitre

Kurdish fighters surround a surrendering woman as ISIS abandons the town of Baghouz, Syria in March. Women who joined or were forced into ISIS need guidance away from an oppressive version of Islam, a Kurdish female fighter says. “They understand the religion in the wrong way.” Photograph by Lynsey Addario

Knight Mai (left) and Florence Stima (right), who are South Sudanese, work at a salon in Uganda's Bidibidi refugee camp. Each makes less than five dollars a week. Small businesses have filled out market areas, but few private companies have tapped into the labor potential of the camp. Photograph by Nora Lorek

In Tinun, Mexico, Beatriz, 18, combs her son André’s hair after a bath. Beatriz is a beekeeper and learned the craft from her grandfather Anastacio Balan Osalde, who passed away two days earlier. Photograph by Nadia Shira Cohen

Feeling dizzy and weak six months after giving birth, Zamzam Yousuf, 35, came into a clinic in the village of Habasweyn in Somaliland run by the Edna Adan University Hospital. Her blood pressure was extremely high. Yousuf was treated by student midwife Farduus Mubarak, 22, under the watchful eye of the hospital’s founder, Edna Adan Ismail, 81. PHOTOGRAPH BY LYNSEY ADDARIO

Aisha Barka and her daughter, Mariam, hadn’t eaten in days when they arrived in an Eritrean refugee camp in 2008, driven from their home by drought, which killed all their animals. After the Eritrean military began abducting young men, people fled for safety across the border into Ethiopia. Photograph by John Stanmeyer

Children nap at a kindergarten in Mongolia’s Bayanzurkh District. Each room is equipped with an air purifier, in an attempt to lower the level of indoor air pollution. Children are especially vulnerable to poor air quality. PHOTOGRAPH BY MATTHIEU PALEY

Pedestrians, shoppers, and people-watchers stroll on Chuo-dori in Ginza, one of Tokyo’s busiest destinations. Cars travel on the street during weekdays, but on weekend afternoons a one-mile strip is closed to traffic and becomes a promenade. Cafés, high-end boutiques, and street performers attract local residents and visitors. Photograph by David Guttenfelder

Young men from Niger and elsewhere wait in a migrant “ghetto” in Agadez, Niger, for a caravan to Libya. With low life expectancy, limited educational opportunities, and a high poverty rate, Niger ranks at the bottom of the UN’s Human Development Index. Photograph by Pascal Maitre

Sal Thegal dressed like a hot dog at the Minnesota State Fair on Friday, August 23, 2019. Photograph by Ackerman + Gruber

Jorge Castellon, an employee at the Saguaro Hotel in Palm Springs, California, poses with a fan (used for dancing) in May 2019. When not working at the Saguaro, Castellon is a professional dancer and dance instructor. “Palm Springs is like a paradise—it’s heaven on earth,” says Castellon. “The people who come here are unique and visit with a purpose, to have fun. We’re just here to play!” Photograph by Jennifer Emerling

Patricia Frazier carries the flag of Benin, the modern nation once ruled by the king of Dahomey, who sold 110 captives to the captain of the Clotilda—the last known ship to bring enslaved Africans to American shores. “If they find that ship, I think it will make people more aware of our history,” says Frazier before the vessel was found. “Sometimes you need something tangible to spur those memories.” Photograph by Elias Williams

Malaysia, 40, poses for a story about the Stonewall riots of 1969 that sparked riots and 50 years of a national LGBTQ civil rights movement. “In life things tend to show you not your wants but your needs. And, transitioning into Malaysia ... has opened up a world of acceptance for me. Because now I am comfortable, and I've never been this comfortable in my life.” Photograph by Robin Hammond

Joseph Wachira, a keeper at the Ol Pejeta Conservancy in Kenya, says goodbye to Sudan, the last male northern white rhinoceros. Sudan died in 2018. Two females of the subspecies remain. Photograph By Ami Vitale

A hunter from a village in Indonesia says he delivers pangolins to the city of Surabaya on a weekly basis. Pangolins are protected by national laws in the countries where they’re found, and international commercial trade in them is banned. Even so, poaching and trafficking are major threats to pangolins’ survival. Photograph by Brent Stirton

A Temminck’s ground pangolin named Tamuda searches for a meal of ants or termites at a rehabilitation center in Zimbabwe. He was rescued from illegal wildlife traders, who likely would have smuggled his scales to Asia for use in traditional remedies. Photograph by Brent Stirton

Late in the dry season, a remnant pool in the Mussicadzi River channel attracts a mob of hungry birds, including storks, egrets, and hammerkops, along with a couple of thirsty waterbuck in Mozambique's Gorongosa National Park. Gorongosa’s avian richness swells further in the wet season, when nomads arrive to feed. Photograph by Charlie Hamilton James

A crocodile rests in Mozambique’s Gorongosa National Park, where wildlife’s future depends on humans’ livelihoods. Photograph by Charlie Hamilton James

Once or twice a month during Costa Rica’s rainy season, female olive ridley sea turtles come ashore by the tens of thousands and lay eggs in a mass nesting event known as an arribada. Hatchlings begin emerging about 45 days later. Photograph by Thomas P. Peschak

Wolves in the Canadian Arctic pick at the remains of a muskox. To get this image, photographer Ronan Donovan placed a camera trap inside the carcass. The pack returned to feed on and off for a month. Photograph by Ronan Donovan

All clear? A New York City rat peeks out from a stormwater catch basin. Photograph by Charlie Hamilton James

Two rats at India's Karni Mata Temple box to determine which is dominant. Rats are social animals that take good care of their offspring. Studies show they will free a fellow rat from a small cage—even if it means giving up a treat. This suggests to some researchers that rats feel empathy. Photograph by Charlie Hamilton James

Behind netting, a polar bear dances at the Circus on Ice in Kazan, Russia. Performing polar bears are extremely rare. The show’s four bears wear metal muzzles, and their trainer, Yulia Denisenko, carries a metal rod. Between tricks, the bears lie down and rub themselves on the ice. Photograph by Kirsten Luce

Confiscated songbirds that were seized from illegal owners are released after weeks in a rehab aviary where they strengthened their wings and learned to fly again. Photograph by Karine Aigner

Inmates at the San Francisco Gotera prison who have renounced their gang ties pray together. Prison-based evangelical churches in El Salvador are growing. Photograph by Moises Saman

Thousands of migratory songbirds are caught around Florida each year to supply a thriving illegal market. Before seized birds are released back into the wild by law enforcement, they are put in an aviary for several weeks where they learn how to fly again as well as how to “find” new food. Photograph by Karine Aigner

Clay, Daniel, and Enzo, three of 39 tigers rescued from an animal park in Oklahoma, gather at a pool at the Wild Animal Sanctuary in Keenesburg, Colorado. These cats will live out their lives here, with proper nutrition and vet care. Photograph by Steve Winter

Nine of 24 lions are darted and flown from Tembe and Mkuze game reserves in Kwazulu Natal, South Africa, to Mozambique in June 2018. The wild lions will be released into the Zambeze Delta there. The move is the largest conservation transport of wild lions across an international boundary in history. A hundred years ago, there were over 200,000 wild lions living in Africa. Photograph by Ami Vitale

Lions that were released and collared in a remote region of the 4,500-square-kilometer Zambeze Delta area of Mozambique lounge in the early morning mist. Mozambique’s wildlife was decimated by the country’s civil war and subsequent poaching in the past 20 years. Today, leading researchers estimate Africa's lion population to be 20,000 or less, with lions now extinct in 26 African countries. Mozambique's ecosystem has made a remarkable recovery—except for its lions. Photograph by Ami Vitale

Shadows form over the Deser-est Motor Lodge in Ely, Nevada. Before it was known as the Loneliest Road in America, Route 50 was a thruway during the 1850s gold rush. Photograph by Mathias Svold

In northwestern Colombia, hunters have long employed their own form of camouflage: masks made of broad, sturdy leaves known as “hojancha.” These masks are used in order to sneak up on turtles and other game animals such as wading and migratory birds. Hunting is still a vital activity for subsistence farmers in the region. Photograph by Gena Steffens

Wearing a parka sewn by her mother, Ashley Hughes spent her 10th birthday camping with friends and family at Baffin Island's Ikpikittuarjuk Bay in Canada. Hughes took part in the Inuit community’s annual ice fishing competition for arctic char. Photograph by Acacia Johnson

Outside a Tokyo drugstore, a stand-in photo board of an apprentice geisha in traditional costume waits for someone to fill its face cutout. Photograph by David Guttenfelder

Japan’s obsession with all things kawaii (which can mean cute, cuddly, or lovable) is on display at Tokyo's Ueno Park as owners line up their pets for a portrait shoot. The kawaii aesthetic of cute culture has been one of Japan’s most successful exports, driving pop culture trends in fashion, technology, video games, and cartoons. Photograph by David Guttenfelder

A group of climbers makes its way along Japan's Mount Fuji Yoshida Trail. Photograph by David Guttenfelder

At 34 weeks pregnant, Brittany Capers, 28, and DeAndre Price, 25, enjoy their baby shower in Washington, D.C. Capers is a perinatal community health worker at Mamatoto Village, a center that supports families during pregnancy and the first six months of a baby’s life. She safely delivered a baby boy last June. PHOTOGRAPH BY LYNSEY ADDARIO

The blue glove hasn’t been in the water long enough to suffer the fate of most ocean plastic, which is to be shredded into small bits, or microplastics, by waves and sunlight. The larval fish below the thumb is a driftfish; the striped one at the base of the index finger is a mahi-mahi. Photograph by David Liittschwager

On an assignment about stem cells that forced him to reconsider his life choices, Max Aguilera-Hellweg shot this photo of pathological specimens in Berlin. Photograph By Max Aguilera-Hellweg

Andres Pedro Osmolski, who goes by “El Gaucho,” organizes beaver spotting tours on the land behind his home in Argentina. He negotiated an agreement with the government to spare the beavers on his property for now so he can continue showing them to tourists. Photograph by Luján Agusti

A headdress of macaw feathers adorns the skull of a sacrificed child who had shoulder-length hair. Researchers say the headdress indicates the youth may have been from an elite family of the Chimu culture in what is now Peru. Photograph by REBECCA HALE, NGM STAFF

This image looks almost abstract. Part of a sculpture by Alexander Calder, perhaps? No. It is the bright red stigma of the saffron flower, Crocus sativus. It takes roughly 170,000 flowers and their stigmas to produce one kilogram of saffron. As a result, it is one of the most expensive spices in the world. Photograph by Martin Oeggerli

Incahuasi, “House of the Inca” in Quechua, was an island when Bolivia's Salar de Uyuni salt flat was a lake in prehistoric times. A remnant of a volcano, it’s covered in cacti, some towering 40 feet, and fossilized algae. Extracting lithium from under the salt flat is certain to alter the spectacular landscape. Photograph by Cédric Gerbehaye

The indigenous Aymara population harvests and sells salt crusted on the surface of Bolivia's Salar de Uyuni salt flat, while lithium—a lucrative resource—is dissolved in brine found deep underground. Photograph by Cédric Gerbehaye

The village of Newtok, Alaska, population 380, is sinking as the permafrost beneath it thaws. On a summer bird hunt, four Yupik boys—from left, Kenyon Kassaiuli, Jonah Andy, Larry Charles, and Reese John—cross a flooded walkway. Photograph by Katie Orlinsky

A polar bear inspects a car near Kaktovik, Alaska. Melting sea ice is driving more bears onto land in search of food—just as thawing and flooding ice cellars are forcing more Alaskans to store fish and meat outside. Photograph by Katie Orlinsky

When sea ice ages, the salt sinks into the ocean, leaving fresh, drinkable water on top. Charlotte Naqitaqvik collects a teapot of water at her family’s hunting camp in Nuvukutaak, near the community of Arctic Bay in northern Canada. Photograph by Acacia Johnson

Josiah Olemaun, a young Inupiat whaler in Utqiaġvik (Barrow), Alaska, takes a breather while stacking whale meat in his family’s permafrost cellar. Photograph by Katie Orlinsky

After making his way in 2016 from Senegal to the agricultural belt of southern Spain, Mbaye Tune settled into regular seasonal work on tangerine and other fruit farms. Now 25, he’s landed legal residency and a rented apartment he shares with other Senegalese. Photograph by Aitor Lara

Angelo Martín Flores Chambi takes a break for a snack in his family’s Chevy pickup while his parents, brothers, and sisters extract salt from the Salar de Uyuni salt flat in Bolivia. Children attend school during the week but help their parents on weekends. Photograph by Cédric Gerbehaye

Ana Ham cleans a pig's head at the Temporal Mennonite Camp in Mexico. The family gives the head and the interior parts of the pig to their Mexican employees as they do not eat those parts. The Mennonites believe that when pigs are slaughtered during the small moon, the meat is drier and therefore easier to handle when butchering. Photograph by Nadia Shira Cohen

A group of beekeepers in Tinun, Mexico, tend to their hives in the off-season. Flowers are just beginning to bloom, and the bees are getting ready to start polinating. Photograph by Nadia Shira Cohen

Peter Peter, 10, rides in his father's soy truck at the Nuevo Durango Mennonite Camp in Campeche, Mexico. The season's soy harvest is ready to be weighed and then deposited in the silo where his father, David Peter, works. Photograph by Nadia Shira Cohen

Wilmer Flores, his face shielded to protect against sunburn, collects salt near the Salar de Uyuni salt flat in Bolivia. Photograph by Cédric Gerbehaye

Spencer Robertson pauses after knocking down Fire 323, ignited by a lightning strike near Bettles, Alaska. About 10 out of more than a hundred applicants are selected for Alaska smokejumper training each year. Candidates must already have wildland firefighting experience. Photograph by Mark Thiessen, NGM Staff

Matt Oakleaf, camera mounted on his gear bag, drops behind the rest of his team to a landing site near smoldering boreal forest in Alaska. Smokejumpers can put on 100 pounds of gear and get on a plane in minutes. Their mission: Extinguish fires before they rage out of control. Photograph by Mark Thiessen, NGM Staff

At dusk, a swarm of bats disperses to hunt in the rainforest surrounding Deer Cave in Borneo. One of the planet’s largest underground passages, it holds more than two million bats. Photograph by Carsten Peter

Thick stands of stalagmites rise from moon-pale banks of sediment in the Drunken Forest—a cave in Borneo named for formations that tilt at unusual angles. Photograph by CARSTEN PETER, PANORAMA COMPOSED OF FOUR IMAGES

Borneo's Deer Cave is home to more than two million bats of several species, which usually fly out in the evenings to hunt. Photograph by Carsten Peter

A World Health Organization team checks the temperature of seven-year-old Confirme Masika Mughanyira in Vayana town, a small village two hours from Butembo in the Democratic Republic of the Congo. Confirme lost both her parents, her older brother, and her younger sister to Ebola. As the only survivor in her family, she's now in the care of relatives. Photograph by Nichole Sobecki

Kavugho Mukoni Romelie, 16, is treated for Ebola at the Alliance for International Medical Action center in Beni, in the Democratic Republic of the Congo. Photograph by Nichole Sobecki

Friends and family of police officer Tabu Amuli Emmanuel grieve during his burial in Kitatumba Cemetery in Butembo, in the Democratic Republic of the Congo. A policeman and father of six, he was killed by armed men while defending an Ebola treatment center run by Médecins Sans Frontières. Photograph by Nichole Sobecki

A woman stops to wash her hands with a chlorine solution upon leaving the hospital in Kyondo, in the Democratic Republic of the Congo. The World Health Organization has set up several Ebola response camps in areas like Kyondo, outside the major cities, where small clusters of Ebola patients have been found. Photograph by Nichole Sobecki

Fourteen-year-old Danila holds a baby alpaca near Huaylillas in the highlands of northern Peru. Photograph by Robert Clark

Fisherman Arnovis Guidos Portillo watches his daughter and son in their home in El Salvador. After reaching the U.S. together in May 2018, father and daughter were detained by immigration authorities and kept in different facilities for more than a month before being deported separately to El Salvador, where they reunited. Photograph by Moises Saman

The pool scene turns chaotic at the Caliente Tropics Resort in Palm Springs, California, during Tiki Caliente in May 2019. The annual event celebrates the love of tropical island living, with Tiki enthusiasts and collectors taking over the resort for the weekend to immerse themselves in a sensory-driven, escapist world that celebrates the music, art, clothing, and cocktails of Tiki culture. Photograph by Jennifer Emerling

The Zeitoun family (Thierry, Nathanael, Gabriel, and Yael) enjoy the view from their new building rooftop, in Jerusalem. Photograph by William Daniels

Bhagavan “Doc” Antle (far right) poses with his staff (left to right), Kody Antle, Moksha Bybee, and China York, in a pool used in his tiger show at Myrtle Beach Safari in South Carolina. Young cubs are a big part of the business; packages for playing and having photos taken with them run from $339 to $689 a person. At about 12 weeks old, cubs are considered too big and dangerous for tourists to pet. Photograph by Steve Winter

Laurance Doyle of Principia College and the SETI Institute communes with some “extraterrestrial” intelligence at Six Flags Discovery Kingdom in Vallejo, California. Doyle’s studies of the communication systems of dolphins and whales could help scientists decode patterns in alien languages. Photograph by Spencer Lowell

Using old but still reliable technology, Russia launches a Soyuz rocket in March from its Baikonur Cosmodrome in Kazakhstan. Photograph by Dan Winters

In a fire treatment session in Chengdu, China, an alcohol-soaked cloth is draped over a patient and set alight to warm the skin and open the pores; an herb-infused oil is then applied. The therapy aims to treat joint pain and other ailments, but research has yet to prove such claims. Photograph by Fritz Hoffmann

At a clinic in Beckley, West Virginia, Jeff Hendricks receives acupuncture and a plant-burning technique called moxibustion to ease pain related to four years of military service. He suffers from a brain injury, bulging disks in his neck, bone spurs, headaches, numbness in his hands, and PTSD. The Veterans Administration-approved treatment reduces the need for conventional drugs. Photograph by Fritz Hoffmann

At China's Chengdu University of Traditional Chinese Medicine hospital, twin sisters Zheng Yue and Zheng Hao wear medicinal patches that contain a formula of herbal medicine used as a seasonal treatment to expel heat from the body during summer. Photograph by Fritz Hoffmann

This book is a romance novel, but National Liberation Front (ELN) Comandante Yesenia also reads aloud to her river outpost compatriots from works of ideology and ELN history. At 36, she has spent more than half her life as a guerrilla fighter in Colombia; her two children live with civilian relatives. Photograph by Lynsey Addario

In South Sudan, Rose Asha Sillah, shown with her daughter, helped start a timber company that grew into a 35-employee operation. In Uganda's Bidibidi refugee camp, she launched a women’s center that teaches skills such as embroidery and farming to about 400 women. Without financial institutions, even innovative entrepreneurs struggle, but Sillah thinks it’s worth it. “Will we spend 10 years crying for South Sudan?” she asks. “We need to look forward.” Photograph by Nora Lorek

Robert Waldron (left), 79, with his husband, Vernon May, 79, was interviewed for a story about the 50th anniversary of the Stonewall uprising: "The LGBT community has come a very, very long way." Photograph by Robin Hammond

Fourteen-year-old twins Sidra (at left) and Shahed remember the barrel bombs in Aleppo, Syria, that forced them from their home in 2013. "We were happy to leave the bombs and the warplanes," Sidra says. The sisters enrolled in Arabic-language schools in Gaziantep and are now in Turkish schools. "From the moment we were displaced," says their father, "I was determined that my children would not stop school." Photograph by Emin Özmen

The majority of residents in Uganda's Bidibidi refugee camp are children, many of whom also work to help their families. In a small shop near his home in Zone 5, 13-year-old Steven Ladu sells candy. Photograph by Nora Lorek

Susan Meneno holds her year-old daughter in front of her family’s sunflower field in Uganda's Bidibidi refugee camp. No one in her family has a job, but some earn money harvesting crops, and she dreams of opening a clothesmaking business. Photograph by Nora Lorek

Lavender (Lavandula spp.) has long been used to perfume homes, food, and drinks. It offers a feeling of warmth, a sort of aromatic welcoming. Up close, it is something else entirely, a desert scene complete with spiny, cactus-like hairs meant to keep herbivores away and hold water in. Photograph by Martin Oeggerli

Former gang members hang from their hammocks inside the San Francisco Gotera prison in El Salvador. Photograph by Moises Saman

Starting at 5 a.m., migrants line up at the border in Guatemala waiting for officials to let them cross into Mexico. When it appeared they wouldn’t legally be let in, hundreds of people walked across a shallow section of the river into Mexico. Photograph by Moises Saman

Hundreds of Central American migrants cool down, bathe, and clean their clothes in the Novillero river in the town of San Pedro Tapanatepec, in Oaxaca, Mexico. The migrants stayed in San Pedro for two nights before resuming their way north toward the U.S. border. Photograph by Moises Saman

A convoy of pickups packed with Nigeriens and other Africans begins a three-day trek from Agadez, Niger, through the Sahara to Libya. Many migrants intend to work there; others hope to reach Europe. Photograph by Pascal Maitre

A local street coal seller stands in Bayankhoshuu, one of the most polluted neighborhoods of Mongolia's capital, Ulaanbaatar. PHOTOGRAPH BY MATTHIEU PALEY