Add Yahoo as a preferred source to see more of our stories on Google. The Lava River Cave exhaled chilled air. I put on my sweatshirt, despite the hot July day. Though I'd been warned about the sudden ...

Another world greets you just a short 30-minute drive from the Icelandic capital Reykjavik. Raufarhólshellir Lava Tunnel is a terrific example of a lava cave created following a volcanic eruption ...

There is something quietly disorienting about standing in the middle of a high desert and realizing the ground beneath your ...

Sometimes, a hole in the ground is just a hole. Other times, it’s a portal to an underground cave spanning miles in width and length. You don’t really know what’s inside unless you dive into the void.

See more of our trusted coverage when you search. Prefer Newsweek on Google to see more of our trusted coverage when you search. A large lava tube—a cave formed from a volcanic eruption—was discovered ...

While the vast majority of our nation’s natural wonders exist above ground, a select few parks, forests, and national monuments feature a hidden basement level. Mammoth Cave National Park, for example ...

In the not-too-distant future, the search for signs of life on Mars and the moon could see the next generation of robots exploring a new frontier: subsurface lava tubes. These missions could also help ...

(CNN) — People who lived in the Arabian Peninsula thousands of years ago went underground when they wanted to beat the heat. Possibly stopping there as they traveled between oases and pastures, they ...