A little more than three years ago, I joined a team of archeologists on an expedition to La Mosquitia, a remote mountain wilderness in eastern Honduras. For centuries, the region had been rumored to contain a lost city, known as the City of the Monkey God or the White City, and now, thanks to a combination of luck and modern technology, an ancient settlement had been found. Although it was probably not the lost city of legend, it was a very real place, built by a mysterious civilization that flourished long before Columbus arrived in the Americas. Hidden in a densely forested valley, it had never been explored. We helicoptered in, set up a base camp, and spent the next nine days slowly uncovering the city’s remains—large plazas, geometric mounds, irrigation systems, extensive terracing. At the base of a small pyramid, we discovered a cache of ceremonial stone sculptures that, when excavated, in 2016 and 2017, amounted to almost five hundred pieces. Many of them are now on display at a newly opened museum and archeological laboratory, Centro de Investigación Ciudad Blanca, near Catacamas, the closest large city to the ruins.

The valley held other surprises. When we arrived, we found that the animals there appeared never to have seen people before. Spider monkeys gathered in the trees above us, hanging by their tails, screeching their displeasure, shaking branches and bombarding us with flowers. Large cats prowled through our camp at night, purring and cracking branches. A tapir and peccaries wandered about, seemingly unafraid, and the area was overrun with venomous snakes. Here was a pristine ecosystem, as obscure to human knowledge as the lost city itself.

When the discovery of this apparently forgotten world was first reported, Conservation International, one of the world’s leading environmental organizations, sent a team of twelve biologists into the valley to do a “rapid assessment” of its ecology. Most of the biologists were from Honduras or Nicaragua, and many had done research in the Mosquitia region before. The expedition’s leader, Trond Larsen, described it as an “ecological SWAT team.” The group’s goal, he explained, was “to quickly assess as much of the area’s biodiversity as we could in a ten-day blitz.”

Using the old base camp as a reference point, Larsen and his colleagues cut four miles of trail in each of the four cardinal directions. As they slashed their way through the jungle with machetes, wading rivers and climbing slippery mountains, they documented, photographed, and collected specimens of the local flora and fauna. Along streams and animal trails, they also set up twenty-two motion-activated camera traps, which took ten-second videos or series of pictures when creatures passed by.

“Our team was astounded,” Larsen told me. The ecology of the valley was indeed pristine, showing little evidence of human entry for a very long time, perhaps centuries. Species that are rare and even thought extinct outside the valley were found in abundance inside, including varieties of butterflies, birds, bats, snakes, and big mammals, as well as critically endangered plants. The spider monkeys showed an unusual color pattern, suggesting that they might belong to a new subspecies.

The biologists were particularly surprised by the density of cats in the valley—jaguars, pumas, ocelots, jaguarundis, and margays. They saw signs of them everywhere. One night, Larsen decided to take a quick hike upstream from base camp to look for glass frogs. He reached a point where the river narrowed in a canyon and was joined by a stream. “I turned around to take a piss,” he recalled. “I looked up and saw these eyes crossing the stream. They paused when they saw me and slowly started moving toward me.” Because Larsen’s headlamp was running out of power, at first he could see only the glowing eyes. As the animal crept closer, the feeble circle of light illuminated the golden, muscled form of a puma. “It came forward very low on its haunches,” he said. “It was maybe about eight feet away when it stopped.” It crouched, as if ready to pounce. “It was obviously curious, but there may also have been some concept in its mind of, Is this something I could eat?” Larsen said.

Panthera onca. The jaguar is the king of neotropical forests, where it is the largest of the cats. Its presence at the White City indicates an extensive, thriving ecosystem. © Washington State University, Panthera, Wildlife Conservation Society, Zamorano University, Honduran Forest Conservation Institute, Travis King, John Polisar, Manfredo Turcios

As the two apex predators—human and cat—took each other’s measure, it seemed to Larsen that time was suspended. Then the puma turned and disappeared into the night. Only afterward did Larsen feel his hair begin to stand up with fear. He flashed the light about, looking for the shine of the cat’s eyes, feeling very alone and concerned that the puma might be waiting in ambush. He walked “rather briskly” back to camp, nervously probing the forest with his light beam. When he arrived and the adrenaline rush subsided, he realized that his zipper was still open.

The camera traps collected images for six months. Last September, a Honduran biologist named Manfredo Turcios Casco returned to the valley to retrieve the cameras for Conservation International. He nearly perished in the effort. The rivers were swollen from torrential rains, and Turcios was swept away several times trying to cross them, losing some of his gear in the process. He was assaulted by disease-bearing insects, including sand flies carrying leishmaniasis. He battled an eye infection and went without food for two days when the helicopter was delayed by bad weather. “When you are alone there, it is like someone or something is watching you,” he told me. “You can feel eyes, or a force, following you. There is like a guardian in that place. That is very scary.” Even so, it was an inspiring experience. “This is the most incredible record of species I’ve ever seen,” he said. While collecting the camera traps, he and the Honduran Special Forces soldier with him, a Miskito Indian from the region, spied a most unusual animal that neither had seen before. It “had the head of a giant rodent,” Turcios recalled, “with a hairy tail” and was about two and a half feet long. With the help of an artist, Turcios worked up a drawing of the mysterious creature immediately after his return. Whether the animal is a mammal unknown to science (something almost unheard of), a variant or mutant, or a species outside its normal range, are all open questions.





1 / 7 Chevron Chevron Photograph by Trond Larsen / Conservation International Bothriechis schlegelii. The eyelash viper is highly venomous and is often hard to see where it blends in with moss at the base of a tree. Sharp scales above the eyes give the appearance of eyelashes.

Turcios was able to recover nineteen of the twenty-two camera traps, containing fourteen thousand photographs and video clips. They are currently being reviewed by biologists at Conservation International. The organization shared a selection of these images with The New Yorker, most published with this article for the first time.

C.I.’s goal was to gather biological information about the valley to help the Honduran government make decisions about its protection, and to justify the benefits of conservation. Illegal clear-cuts for cattle grazing reach within ten miles of the valley’s entrance. Now, with the area established as an “extraordinary, globally significant ecological and cultural treasure,” Larsen said, there’s a chance to halt the deforestation. After the discovery of the lost city, the President of Honduras, Juan Orlando Hernández, took steps to protect the valley. “C.I. can help the government accomplish that,” Virgilio Paredes, the Honduran official who coördinated the expeditions, told me. “We need international support.”

Conservation International’s rapid-assessment survey was a coöperative effort among the following individuals and entities: Steve Elkins; Bill and Laurie Benenson; Conservation International; the Wildlife Conservation Society; President Juan Orlando Hernández, of Honduras; Virgilio Paredes Trapero, the former manager of the Honduran Institute of Anthropology and History; and Ramón Espinoza, the former director of the Honduran Institute of Science and Technology. Major funding was provided by the Francis and Benjamin Benenson Foundation and the government of Honduras.