A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

This Budapest bar allows drinkers to leave their mark on the walls, floor, and even ceiling.

Once the home of a hermetic monk, this cave now houses a small church.

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

A museum of alchemy and a basement laboratory all housed in an ancient building in a Gothic tower.

Microscopic scenes; some call it novelty, some call it art.

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

A crucified and bearded female saint.

Despite attempts by local police to discourage it, Beatles-inspired graffiti has been a means for artists to air grievances for decades.

The first museum in the world devoted to sexual gadgetry.

This Prague museum collects brutalist relics and memories from the country's former Soviet rule.

A saintly relic hidden in a Prague church basement.

An extraordinarily ornate museum in San Diego holds wondrous anthropological treasures.

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

A German apartment building hosting as many trees as human occupants.

The birthplace of an eccentric alchemist and possible inspiration for the fictional reanimator of monsters.

The fairy tale castle of the "fairy-tale king."

From Ancient Rome to WWII, Neupfarrplatz has over 2,000 years of history underneath its main square.

The stones of this formerly witch-obsessed castle were used to build a church.

The prototype for all Nazi concentration camps.

This century-old cinema house has a marquee that has been hand painted by a single man for over 25 years.

One man's personal kunstkammer, museum and shop.

A serious museum dedicated to two German comedians.

What was once thought to be a wellspring of unicorn bones is actually just a prehistoric burial site.