Hidden beneath the streets of London is a secret subway that only carried mail.

A 30-acre garden inspired by the principles of modern physics.

A hotel and restaurant serving as the mecca of kitsch.

An Aztec snake god has taken the material form of an apartment complex.

An abandoned facility that has become a place of ritualistic satanic worship, or so rumor has it.

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

These fantastically named natural pools look like something out of a Scottish myth.

The oldest stone house in Paris was built by its most famous alchemist.

Monasteries on rock pillars, once accessible only by frayed ropes.

Wondrous sandstone hoodoos where Native Americans collected clay for pottery, 9,000 years ago.

The legendary building that needed ghostly approval before being built.

Thousands of exquisitely carved stone water storage wells, hundreds of stone steps fill this exquisite medieval stepwell.

Northern Ireland's Brobdingnagian stepping stones.

Stunning wetlands ablaze with pink lotus flowers.

Famously misunderstood wonder of the ancient world

A walk through the historic city center, under the streets of Seattle.

Site of a former hidden treehouse in New Orleans.

The seamy, underground secrets of Portland's criminal past.

Under the right circumstances, this waterfall in Yosemite briefly turns a luminescent fiery orange.

An underground mansion with fruit-bearing trees and grapes growing beneath the surface of central California.

The ghostly remains of an accidental sea.

A trash dump made beautiful by nature's power.

A snapshot of the city's fascinating voodoo culture.

The abandoned zoo enclosures offer a perfect place to experience the other side of the bars.