The stunning cave in Naica, Mexico, is home to some of the largest crystals on Earth, but harsh conditions can kill those who stay too long.

This feature alone cannot explain the human-size Pulpí Geode crystals, though. Spelunkers rappel 300 feet (90 meters) into the Greenland ice sheet. Glacier caves such as these form when seasonal ...

These underwater caves are amazing natural swimming spots ... Cenote Suytun, located in the Yucatan Peninsula, is a visitor ...

At 4.3 miles long, Parks Ranch Cave in southeastern New Mexico is the second longest gypsum ... dangles from a cottonwood branch over the warm, crystal-clear Black River. Veni steps into the ...

The animals that plummeted 85 feet into Wyoming’s Natural Trap Cave provide a layered history of life dating back to the ...

Scuba diving level: Ras Mohammed is renowned for its vibrant coral reefs and diverse marine life, making it suitable for ...

Two 325-million-year-old ctenacanth shark fossils discovered in Mammoth Cave shed light on ancient marine ecosystems.

The spectacular Silfra Fissure lies within Iceland 's Thingvellir National Park. It is among the rare spots on Earth where you can snorkel between two tectonic plates—the North American and Eurasian ...

Natural Trap Cave is a pit in northern Wyoming into which countless animals have fallen and met their untimely demise since the Pleistocene. Paleontologists today find the cave a treasure trove — a ...