Tulelake, CaliforniaFormed by half a million years of volcanic activity, Lava Beds National Monument contains the highest ...

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 subterranean attraction in Pennsylvania is a gorgeous cave system with plenty of fascinating stalagmites and stalactites ...

Somewhere deep inside a salt cave in Hallstatt, Austria, a small crystal disk stores the entire human genome, and possibly ...

For the last 25 years, intrepid groups of teens have set out to explore, document and preserve some of the most fragile ...