A swing to dangle you off the very edge.

Mother Nature outdoes herself with this stunningly beautiful set of caves carved into marble.

An old vending machine serves up unpredictable beverages from its seemingly magical insides.

The fairy tale castle of the "fairy-tale king."

An eerie, derelict amusement park in Berlin.

A massive underwater sinkhole made famous by Jacques Cousteau.

Medicinal spa created with the discharge from a geothermal energy plant.

This beautiful building in the heart of Manhattan's Financial District was empty for decades.

On the Oregon coast there is a natural hole that seems to be draining the sea.

Most-visited and most-photographed slot canyon in the American Southwest.

A collision of human error and natural geothermal pressure created this rainbow-colored geologic wonder.

The sign at the garden gate reads: "These Plants Can Kill."

A fiery crater has been burning in the Karakum Desert since 1971.

An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.

A lovers' beach, tucked below the surface of the island, provides a safe haven for romance.

This iconic L.A. bookshop is housed in an abandoned bank—both symbolic and chic.

An exquisite tunnel of cascading flowers.

A beautiful, dense forest in the shadow of Mount Fuji, with a tragic reputation.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

The mark of the Devil's horns on a marble column in Milan.

This Italian dam is covered in salt-hungry goats who manage to scale its almost vertical face.

The most gigantic, swoony, intimidating trio of fingers in all of antiquity.

A bathhouse from the second Islamic Caliphate decorated with frescoes of constellations, pleasure gardens, and naked ladies.

The world's oldest map of the holy land gives us a fragmented glimpse of the layout of biblical nations.