Eco-village hidden in the foothills of the Alps that created a massive system of psychedelic underground temples.

Natural stone arches form a walkable "cathedral" at low tide, then disappear entirely when the water returns.

Mirrors and glass shards cover every inch of this arrestingly beautiful mosque.

This neon blue river gets its color from a unique mix of bacteria and volcano minerals.

Discover for yourself what Herb Caen referred to as "the best kept secret in the Bay Area."

Once an unstoppable source of gold and silver, this town came to a grinding stop when the groundwater proved deadly.

An explosion of natural color known as "the river that ran away from paradise."

Dive bar built out of the remains of a whaling ship.

A living snapshot of a different time in America is preserved and maintained by a community of volunteers.

This natural spring not only claims to heal the wounded but it has also been willed to God.

Once home to seven different roller coasters, Glen Echo has undergone many transformations since its founding in 1891.

A spring-fed pool so deep it's used for scuba diving as well as swimming.

A magical sinkhole on the Yucatán Peninsula is adorned with mini waterfalls and hanging vines.

In a largely deserted ghost town, a little brick building recalls its history as a gold rush hub and haven for outlaws.

A beach made of semi-precious green sand on the Big Island of Hawai'i.

The ravine where Jesse James supposedly performed an impossible jump to evade capture.

Race through the maze, get your name on the sign.

This secluded walking trail is a hidden gem of a Pittsburgh park.

Once a place of peaceful repose, this sanitarium now faces an uncertain future.

Travelers leave tea kettles in a remote part of Death Valley as part of a mysterious, decades-old tradition.

An abandoned swimming pool decays on the outskirts of Berlin.

This tiny museum's sizable collection is jammed into a former underground public toilet.

Another of California's unused Cold War missile defense complexes has become a graffiti gallery.

This former Baroque palace on the historic Calle Montcada is a rare architectural gem and was once the meeting place of an aristocratic scholarly society.