A giant leatherback sea turtle is slowly moving back toward Galathea Bay before sunrise. She just finished laying a clutch of eggs and covering them with soft sand. On her way, she passes huge robber crabs, which released their own fertilized eggs into the water. They follow the riverbed north to forage for food. While a crab-eating macaque, who is stretching after waking up, surveys the sand from the tropical evergreen forest above them.

Welcome to the Great Nicobar Biosphere Reserve. The biosphere reserve, which covers 85 percent of Great Nicobar Island, was declared a UNESCO World Heritage Site in 2013. It’s full of mountain ranges, wet forests, coastal plains, and meandering rivers. Endangered animals—including the Nicobar megapode, the Amboina box turtle, and the saltwater crocodile—find refuge here. Plus two tribes, the Shompen and Nicobarese people, live undisturbed by modernity.

Great Nicobar Island is the largest and the southernmost of the Nicobar Islands. The remote islands sit in the Bay of Bengal in the eastern Indian Ocean. They are far from, well, everywhere. Danish missionaries attempted to settle here in the mid-18th century. The British tried to set up a penal colony in the late 19th-century. The Japanese arrived during World War II. None stayed. And the islands have remained largely untouched ever since.

Great Nicobar was named a biosphere reserve to ensure the island remains pristine. Indira Point—with its red-and-white-banded lighthouse—and Campbell Bay are home to the small number of people who moved to the island. They fish, grow corn and coconuts, and harvest betel nuts. But the rest of the island is covered with pandanus, margosa, and beefwood trees. Slow moving rivers, including the Alexandria and the Amrit Kaur, flow south toward the sea. While Mount Thullier, the highest point in the Nicobar Islands, provides a respite from the hot Indian Ocean sun. The island is peaceful, pure, and absolutely beautiful. Hopefully it always remains that way.