A fantastic castle rumored to be the birthplace of King Arthur.

The hallucinogenic center of the ancient world.

Venice's "Island of the Mad."

Architectureal fantasy quarter of Rome.

Started as a kitchen garden, now the second largest botanical garden in the world.

The trials and tribulations of marking Poe's grave.

Iceland's largest lagoon is home to stunning multi-colored icebergs.

A pedestrian island in the middle of world-famous Times Square emits a strange (and purposeful) humming noise.

This little museum is built on a theater that was once a wildly elaborate speakeasy.

Hollywood's most famous landmark, the "temporary" sign that has stood for decades longer than intended.

The most visited, and possibly most controversial, museum in Germany.

Hundreds of lucky felines haunt the ruins where Caesar was murdered.

Stalactites and stalagmites in a beautifully lit cave.

The very center of Paris is surrounded by a bevy of strange good luck rituals.

Walk upon the mementos of the dead in this Parisian courtyard paved with medieval tombstones.

In the middle of an extremely unforgiving and desolate high desert is the most secret military facility in the world.

A book collector's dream, this Toronto bookstore has the world's first "Biblio-Mat," a random book vending machine.

The abandoned husk of a mental institution that failed to save a Jazz Age icon still sits nearly unchanged.

An underwater city for the dead.

A Hawaiian stairway to heaven—that you can't climb.

This churchyard arbor is surrounded by hundreds of gravestones placed there by author Thomas Hardy.

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

Crystal clear lake with a shoreline of travertine located in a Colorado canyon.

A small island less than half a mile from Venice is a forbidden island with a dark and twisted past.