From the deep ocean floor to vast underground caverns beneath our feet, these places challenge our understanding of the world.

The Veryovkina Cave was the deepest-known cave on Earth, and experts stumbled upon it before daring to attempt a dangerous mapping of the depth.

The Hranicka Abyss is at least 1,325 feet deep, and likely goes down further. — -- A team of explorers believe they have discovered the deepest known underwater cavern the world in eastern Czech ...

What started with a UVA caving club now has a Class of 2024 alumnus mapping rivers and crystal chambers in caves across the ...

The park was founded by a former U.S. Navy diver who envisioned a unique underwater spectacle that would bring people from ...

BOB MARSHALL WILDERNESS, Mont. — Montana calls itself home to the first and now second deepest cave in the continental United States. A team discovered Bobsled Cave in the Bob Marshall Wilderness, and ...

Hells Canyon, the deepest river gorge in the United States, likely got rapidly carved 2.1 million years ago when a shifting landscape in Idaho caused a giant lake to start overflowing. That's ...