There aren’t many frontiers left in the world. Explorers have scaled the world’s tallest mountains and taken samples from Antarctica’s deepest subglacial lakes. You can even visit remote locales from your web browser. And yet, some corners of the Earth still remain essentially uncharted by Western travelers. Here are some of the coolest underexplored places around the globe.

1. Vale do Javari // Brazil

This region, home to at least 14 of the Amazon’s uncontacted tribes, is one of the most isolated places in the world, in part by design. An estimated 2000 indigenous people live autonomously from the Brazilian government in an area about the size of Austria. The tribes’ right to live in isolation is protected by a federal agency charged with preventing outsiders from invading indigenous territories.

2. Northern Patagonia // Chile

Home to temperate rainforests, glaciers, fjords, and hot springs, northern Patagonia is one of Chile’s wildest landscapes. It’s the country’s most sparsely populated region and has only been accessible by highway since the ‘80s. The Northern Patagonian Ice Field remains one of the largest masses of ice outside the polar regions.

3. Kamchatka // Russia

Kamchatka, Russia, is a beautiful place to sit down and admire the view.Dmitry Aristov/iStock via Getty Images

Russia’s eastern peninsula is home to some of the most spectacular volcanic activity on Earth, with more than 300 volcanoes, including one that has been erupting continuously since 1996. It’s home to the most diverse range of salmon species and is the most densely populated brown bear habitat in the world. However, the region was closed to Westerners until the collapse of the Soviet Union in 1991, and even before that, only 400,000 people (all with military clearances) were allowed to live in the territory, which is around the size of California.

4. New Hebrides Trench // Pacific Ocean

Located off the eastern coast of Australia, scientists didn’t delve into this submarine trench in the South Pacific seafloor until the end of 2013. When researchers from the UK and New Zealand sent underwater robots into this crack in the ocean floor almost four and a half miles deep, they found prawns and eels totally unlike those found in other deep-sea trenches.

5. Northern Forest Complex // Myanmar

Many of the subtropical forests located on the steep slopes of the easternmost stretch of the Himalayas are virtually untouched by human activity. They're important areas for wildlife: Deep within the forests in Myanmar’s Kachin State lies the largest tiger preserve in the world. It’s also home to bears, red pandas, and gibbons.

6. Tsingy de Bemaraha National Park // Madagascar

Named for the unique, massive limestone formations known as tsingy (Malagasy for “walking on tiptoes”), this 600-square-mile national park and wilderness preserve is located on Madagascar’s western edge. The labyrinth of jagged, needle-shaped limestone was formed by erosion over a period of millions of years, and the resulting habitat of gorges, canyons, and forests is a natural fortress. A huge number of species of plants and animals are endemic to the region, meaning they’re not found anywhere else on Earth, and there are plenty that haven’t even been discovered yet. While its southern tip is open to the public, much of the reserve is off-limits to tourists.

7. Southern Namibia

Dune 7 towers above all the others.Italian photographer in love with travel and photography/iStock via Getty Images

The Namib is estimated to be the world’s oldest desert, and it’s one of the driest, least-populated places in the world. Dunes dominate the southern part of the harsh desert, and there are few paved roads. At 1256 feet tall, the giant Dune 7 is believed to be the tallest sand dune in the world.

8. Star Mountains // Papua New Guinea

This remote region in western Papua New Guinea contains the Hindenburg Wall, a limestone network of plateaus more than a mile high. The 30-mile-long series of bluffs features nearly undisturbed ecosystems high above the ground. A 2013 biological survey of the area found 1108 animal and plant species, almost 100 of which were new to science [PDF].

9. Sakha Republic // Russia

The Siberian Sakha Republic (also called Yakutia) covers 1/5 of Russia (about the same amount of land as India), with a large swath of the territory located above the Arctic Circle. Its climate is one of the world’s most extreme: Average temperatures in January are as low as -33 °F, and most of the land is covered by permafrost. Lichen and moss make it a favorite habitat for reindeer. Though mining has taken its toll on the region’s pristine wilderness, parts of it remain untouched, like the Lena River Delta, a gorgeous refuge and breeding ground for wildlife.

10. Greenland

Though Vikings landed in Greenland around 1000 CE, we’re still discovering parts of the far-northern region. Melting glaciers continue to reveal new islands. Much of the inland part of the country is still uninhabited, as roughly 80 percent of the island is covered by ice cap.

11. Mount Namuli // Mozambique

This almost 8000-foot-tall peak is the largest of a series of mountains that have developed much like separate islands, with very different species making their homes on the different peaks. In 2014, a group of biologists and rock climbers teamed up to conduct fieldwork in the region, where rock climbing is sometimes the only way to get to unexplored habitats.

12. Fiordland National Park // New Zealand

Milford Sound in Fiordland National Park.miralex/iStock via Getty

New Zealand’s largest national park was shaped by glaciers and contains some of the country’s oldest rocks. The vast wilderness is home to a unique diversity of animals, like the takahē, a flightless indigenous bird thought to be extinct for decades until it was rediscovered in the park in 1948, and the kākāpō, the world’s only flightless, nocturnal parrot. Fiordland’s 2.9 million acres are some of the wildest lands in the Southern Hemisphere.

13. Cape Melville // Australia

Walled off by forbidding granite boulders piled hundreds of feet high, Cape Melville is only around 900 miles from Brisbane, one of Australia’s biggest cities—but the rainforest habitat might as well be a world away. Virtually inaccessible except by helicopter, scientists discovered three completely new species of animals in the area in 2013.

14. Son Doong Cave // Vietnam

The world’s largest cave contains its own river and even a jungle. At more than 5.5 miles long, it’s cavernous enough to house a skyscraper! The first expedition set off to explore this underground world in 2009 before being stymied by a 200-foot-tall wall of calcite inside. Much of the surrounding network of over 150 caves near the Laos border remains unsurveyed.

15. North Sentinel Island // India

Located in the middle of the Bay of Bengal off the southernmost tip of Myanmar, North Sentinel Island technically belongs to India, but few outsiders have made contact with the Sentinelese people. There’s a three-mile exclusion zone surrounding the island, where somewhere between 50 and 300 people are estimated to live. The locals’ hostile reactions to outsiders’ attempts at contact have left much of the island unexplored.

A version of this story was originally published in 2015; it has been updated for 2021.