Around 100,000 bodies are buried below the medieval headstones, many of which mark graves with multiple bodies stacked up to 12 deep.

A collection of anatomical samples from one of the first anthropologists to suggest that humans reached North America by crossing the Bering Strait.

Two stunning 17th-century libraries and a cabinet of curiosities.

The slender brass strip in Prague's Old Town Square was used to tell time from 1652 to 1918.

Walk through Czech history in Prague's largest graveyard.

The hidden lair of an alchemist rediscovered in a 2002 flood.

Steadily reminding Czechia of its past.

Street artists transformed an abandoned air vent into the beloved Star Wars robot.

The now-abandoned tunnels were built for the transcontinental railroad on the route where the first wagon train entered California.

This otherwise unremarkable ski town building marks the site of Butch Cassidy's first robbery.

Fortified medieval tower house with lovely roof garden.

Ever hear of the Milazzo Cage?

These spartan apartments are provided to clergymen visiting Vatican City.

More sculpture than building, this architecturally significant temple was built on the spot of Saint Peter's crucifixion.

A mysterious chasm in the heart of the ancient Roman Forum, the Lacus Curtius was once believed to be a gateway to hell.

This ritzy Italian market is built around a statue of an unforgiven heretic who was burned for his belief in an endless universe.

2300-year-old Roman road connecting the empire.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

Architectureal fantasy quarter of Rome.

A submerged village appears when dam levels drop.

This unreal Portuguese palace looks as though it's made from a pile of different castles.

A 16th century chapel decorated with bones, skulls, and entire bodies hanging from the wall.

Stalin's march toward a more modern USSR flooded a monastery, leaving a unique and extravagant nautical marker, "The Flooded Belfry."

The oldest museum in Russia is home to a fascinating collection of nearly two million anthropological artifacts and anatomical curiosities.