Like Mardi Gras, only everyone's a pirate.

This fairytale-inspired cottage was created by a university literature professor.

Originally built for London’s cab drivers, this bright green hut now serves anyone a hot drink or meal.

In Twickenham sits a small whitewashed castle that inspired Mary Shelley's 'Frankenstein.'

Pop culture has helped to keep this iconic British building from being destroyed.

This pub was 238 years old when it decided to revamp its image: It started serving Thai food.

An small and easily overlooked archaeology museum chock full of Egyptian artifacts.

This hidden green space is the city's second largest conservatory.

Wedged between two buildings at the Great Ormond Street Hospital is this secret music installation.

An incarceration museum on the spot of possibly the oldest prison in England.

A charming 17th-century alley is lined with secondhand bookstores and antiquarian shops.

An expansive complex of subterranean tunnels is all that remains of one of Europe's most formidable medieval fortresses.

A silly medieval mural preserved on the side of a Viennese house.

Dug as a secret royal escape route, the tunnel became a wartime bomb shelter and dumping ground for vintage cars.

This quaint Italian town keeps losing ground as the sides of its plateau slowly erode.

Five candy-colored villages on the Italian Riviera.

This head-spinningly bizarre Depression-era art cave is wall-to-wall quartz and Jesus.

Wild lights and sound effects turn a walk through some caves into an eye-popping 1960s tourist attraction.

Hundreds of glow-in-the-dark objects light up a museum in a historic zinc mine.

The largest self-built castle in the U.S., six decades in the making.

An underwater city for the dead.

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

Resting place of Hollywood's immortals is also site of summer film screenings.

These remote Florida islands have a history of sea turtles and sunken treasures, and one of the world's largest coastal brick fortresses.