Within the Saudi Arabian desert lies a 2,000-year-old ghost town made of stone and mud.

Abandoned bridge hidden deep in the San Gabriel Mountains.

A tiny, unassuming park in Tampa that belongs to the Republic of Cuba.

The remnants of a failed socialist commune can still be found just off a California highway.

This famous city eluded concrete detection until the early 2000's.

Some of the tallest ancient American ruins continue to inspire awe and curiosity.

A cave's rare beauty held a cavernous secret hidden underground.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

This geothermal hot spring hides beneath a slowly growing mineral dome.

A clear blue swimming hole with hidden caves, still unexplored.

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

Michael Heizer's masterwork in the Nevada Basin.

This massive geographical sculpture is so subtle, it's possible to pass by it without noticing.

An eccentric artist's abode in this small Italian town has been transformed into a surreal temple of mosaic madness.

The 40-foot-tall votive candle is the largest of its kind.

A collection of massive stacked rocks in Texas includes a snarky note on the benefits of modern technology.

A recreated Stonehenge stands in a country field, complete with Easter Island moai heads standing as sentries.

This sacred cavern, 400 feet deep, is home to millions of bats and an ancient burial ground.

Tracks near this Texas nature site were once thought to support the Creationist belief that man and dino coexisted.

An enormous pink granite batholith, long attributed with spiritual powers by the Tonkawa Indians.

Beneath the city of Lourdes, France is a massive, concrete church.

Modeled after a famous church in Vienna, Austria—but in Helena, Montana.

One of the tallest buildings in Iceland, and perhaps, the most visually impressive.

A spiritual vortex among the red rocks in Sedona.