An ancient stone wall formed by lava that was a frequent stop during funeral marches.

This cramped crevasse saw the entire population of its island suffocated inside its depths.

This Norman castle has been the scene of assassination plots, religious persecution, and Nazi conspiracies throughout its long history.

Its walls are adorned with exquisite murals of the natural world, transforming it into an ecologist’s Sistine Chapel.

An Orthodox church built by the Royal Family for the Russian community exiled to the French Riviera.

Thousands of narrow alleyways in an ancient medieval city make up what's believed to be the world's largest car-free urban zone.

The designated Jewish quarter in Fez dates back to the 15th century.

The walls and ceiling of this Polish church are decorated with thousands of skulls, with another 21,000 skeletons just below.

Underneath this small church are 15,000 bones, arranged by an obsessive academic.

The final resting place to 300 Victorian-era pets hides inside the city park.

The mummified right fist of a 1,000-year-old saint-king sits inside an ornate golden reliquary.

Children's hospital in London that operates on royalties received from Peter Pan, which J.M. Barrie signed over in 1929.

This intricately carved and hilariously huge bed was such a famous symbol both Shakespeare and Byron used it in their writing.

An artistic tribute to the famous singer, just around the corner from where he was born.

A makeshift shrine to the late rock star is still kept up on the nondescript façade outside 1 Logan Place.

Uh, pardon me, ma'am, but I couldn't help noticing that there's a Columbo statue in the middle of Budapest.

The lab where the scientist made his groundbreaking discoveries is preserved on the basement floor of the Faraday Museum.

A museum dedicated to a secret military hospital hidden beneath a castle in Budapest.

This small museum in a former church crypt contains artifacts of the Elephant Man, Jack the Ripper and Florence Nightingale.