A saintly relic hidden in a Prague church basement.

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

Europe's second largest ossuary wasn't discovered until 2001.

Two monstrous faces loom over a village in Czechia.

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

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

The first museum in the world devoted to sexual gadgetry.

Walk through Czech history in Prague's largest graveyard.

Countless grotesque faces stare out from this eerie Prague art wall.

A Jenga-style cylindrical tower of books that appears to go on forever.

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

One of Catholicism's four major basilicas has a series of papal portraits that are said to predict the end of the world.

The best preserved Paleochristian basilica in Rome hides a number of oddities and secrets.

A treasure trove of Renaissance-era funerary art in a Roman church built on top of Nero's grave.

An abandoned Roman salami factory has found new life as an art space home to 200 squatters.

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

This delightful little museum is dedicated to only one thing: pasta.

A Nesting Doll of Churches.

The engineering wonder and pleasure dome of a much-maligned emperor still holds undiscovered secrets.

Architectural monsters are devouring this palace's every door and window.

The skull of the patron saint of lovers lies in the Basilica di Santa Maria in Cosmedin—maybe.

The final resting place of the poets Shelley and Keats.

At the crypt of St. Mary of Eulogies and the Dead you are left alone to ponder mortality among piles of skulls.

The yawning maw of this pagan visage is said to bite off the hands of liars.