The medieval legend behind this holy well was one of the inspirations behind "Alice's Adventures in Wonderland."

This picturesque abandoned home is rumored to be a spite house.

The oldest residential street in Europe also features an optical illusion.

This large, circular tomb is the final resting place of the first emperor of Rome.

No one really knows how these old hobby horses got here, but the herd keeps growing.

The kind of mixed-up place that drives archaeologists crazy.

A French chateau, failed utopian community, odd museum, and Stonehenge replica in rural Washington State.

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

The Jewish diaspora shares a menu at this museum café.

A remarkably opulent mansion with a tragic history.

This medieval sanctuary's tree-framed door looks like a portal to a mythical realm.

This bakery and museum offers tours of the tastes and mythology of Aachen's signature spice biscuit—just don't ask for the recipe.

Just your average Marie Antoinette–themed speakeasy in an abandoned 19th-century subway tunnel.

The fountain marks the area where hundreds of accused witches were burned at the stake.

This "cursed house" features secret rooms, hidden vaults, and dark escape tunnels.

A mysterious tunnel hidden in the shadows of a colorful, historic sanctuary.

A medieval stronghold rising over the ruins of ancient Roman villas along Rome's southern coast.

This breathtaking monastery was established by Saint Benedict himself 1,500 years ago.

Centuries ago, red and white wine poured from the statue's breasts whenever a new Venetian ruler was elected.

A medieval fountain lined with 99 unique stone faces whose origins and meaning remain unknown.

The world's oldest surviving anatomical theater, where "the dead are pleased to help the living."

A sinister pyramid in the Frari contains the heart of the famous neoclassical sculptor.

The skulls and bones of thousands of soldiers line the walls of this small Italian chapel.

A submerged archeological park still holds the wonders of a Roman Sodom.