This subterranean studio is filled with fascinating kinetic art.

A hands-on traveling collection of the innovative devices of yesteryear.

A museum dedicated to the Spanish occult in a town that was terrorized by the Inquisition.

Overlooking a Scottish loch, this beautifully crumbling castle once inspired a poem by William Wordsworth.

A 19th-century subterranean reservoir repurposed as a contemporary art cave.

This mysterious underground cave in Shropshire dates back to the 18th or 19th century.

Its town washed away centuries ago, this lonely tower by the sea tells the tale of a mermaid and a curse.

A century-old network of freight tunnels underneath the city's historic business district.

Britain’s longest ancient monument, this great 8th century earthwork was built to mark the boundary between what would become England and Wales.

French commune at the heart of conspiracies.

This French castle is said to have once held the Holy Grail but is now a gorgeous mountaintop ruin.

This religious complex carved into a cliff is steeped in legends of miraculous stags and the Holy Grail.

Mexico's first public cable car soars over the congested streets outside Mexico City.

A picture-perfect town, perfect for blowing up.

Stepping away from the glitz of mobsters and casinos to learn about the other history of Vegas.

A nostalgic bibliographic gem.

Hidden amid the tropical forest in the Caribbean Sea are the decaying ruins of the Cocaine King's luxurious island party home.

A tongue-in-cheek arcade where the games are based on everyday life.

Graffiti covers the walls of a room where university students through the centuries have waited nervously to defend their theses.

This splendid tomb may look fantastic, but there's nothing in it...

This whimsical castle of grottoes was the labor of love of a French postman, and one of the greatest achievements of outsider architecture.

The largest collection of handbags in the world, the oldest of which were used to carry Bibles, primarily by men.

This unassuming museum's slogan translates to “there is a limit of sadness, anxiety has no limits."

A former palace transformed into a mausoleum for North Korea's supreme leaders.