A Rodeo for Prisoners.

Explore the largest pure gypsum deposit in the world, and go dune sledding while you're at it.

Performers, intricate sets, and a real speakeasy tell the story of the 18th Amendment.

This demon atop the Notre-Dame de Paris looks utterly bored.

This medieval tower is all that remains of the castle where Joan of Arc was held before being burned at the stake.

J.R.R Tolkien, C.S. Lewis, and other "Inklings" met at the Oxford pub to discuss the now legendary fantasy stories they were writing.

The names Lúthien and Beren can be found inscribed on the shared grave of the famous writer and his beloved wife and muse.

This massive subterranean fissure is known as the "underground Grand Canyon."

This domed temple was built in a hidden cave mouth as a refuge for sinners seeking absolution.

Beautiful views and Roman-style statues on the Italian coast.

The first declared National Monument in the United States.

A cemetery housing wild west legends in South Dakota.

A mountain pass in Bulgaria's Balkan Mountains was the site of four historic battles.

A magnificent, glittering building tucked into a tiny Bulgarian mountain town.

This massive underground salt mine now holds a sci-fi theme park in its depths.

A cave network located at the southernmost tip of mainland Greece was once believed to be an entrance to Hades.

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

It houses the remains of a 17th-century version of the Titanic.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

Sweden's first nuclear reactor, R1, can be visited 25 meters underground.

Now a hotel, this former bank was the site of a robbery that spawned a psychological phenomenon.

An electrifying collection of gadgets and literature from the 16th through 20th centuries.

A legal loophole makes it possible to get away with murder within this 50-square-mile section of Yellowstone.

These old stone ruins in the Oregon wilderness were once bathrooms and are steeped in legends of murder.