Abandoned railway line circling the city of Paris.

The ruins of a Duke's bucolic dream, where camels once roamed alongside "Dutch" windmills and faux-Italian vineyards.

Half a century after it was abandoned, this ghost town is coming back to life.

The hallucinogenic center of the ancient world.

A spectacular cave and a beguiling lake.

A counter-culture bookstore like no other hides in plain sight in the streets of Paris.

According to legend, this cavern holds the passage that Persephone used to travel to and from the underworld.

A minotaur, a labyrinth, and a dubious restoration pull in visitors from around the world.

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

According to legend, this ancient column contains healing properties.

Legend says this sacred tree was a gift from goddess Athena.

A sprawling collection of books and manuscripts about ancient Greece that would have put their famed libraries to shame.

Heralded as the world's first theater, these ruins are often overlooked as they reside in the shadows of the Acropolis.

The Cycladic architecture makes this Athens neighborhood feel like an island paradise hidden in the shadow of the Acropolis.

This mystical orb covered in strange symbols is thought to have been used in ancient Greek magical rituals.

Three columns of volcanic rock shoot out of the ocean.

This wrecked airplane has been sitting on a black sand beach since the 1970s.

This modern monument to pagan belief looks like it was transported straight from ancient times.

A fantastic reconstruction of a 10th-century Viking longhouse.

This natural rock formation features seemingly unnatural vertical ridges that have been blamed on elves.

Icelandic folklore says this giant boulder was ripped from the mountains and placed at its current location, where it became home to elves.

The oldest hall in Iceland was written of in the Sagas and features a centuries-old escape tunnel.

This scenic Icelandic lava flow is named for a pair of Berserkers who were murdered, according to a famous Saga.

A winding, blood-red tunnel of hardened lava navigable by foot.