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

A mocking tribute to the past and modern leadership of Prague.

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

Two monstrous faces loom over a village in Czechia.

A 400-year-old mummified arm dangles from the ceiling of St. James the Greater, serving as a warning to thieves.

The risqué mixed-media sculptures are supposedly a metaphor for Czech politics.

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

What looks like a suicide in progress is actually a statue of Sigmund Freud.

A bust of Franz Kafka spins in pieces, reflecting the writer's inner torment.

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

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

This impressive collection of skulls and bones was gathered by an ex-zookeeper who took advantage of a pig plague.

A fascinating and enormous collection of natural history exhibits stained by a dark colonial legacy.

The bronzed skull of a beheaded traitor was affixed to the city gate in the 17th century.

When you're a great Russian Tsar, even your vomit gets a statue.

A Museum of Psychiatry in a still-operating mental institution.

Christ's blood preserved in a Belgian town.

Medical history with an amazing, if frighting, collection of wax diseases on display.

A Belgian self-built tower inspired by the Bible and ancient civilizations.

Hiding the longest subterranean river known in the world.

A magical and peaceful ruined Cistercian abbey in what is now southern Belgium.

Part modern art project, part traditional chapel, this see-through church is only substantial from the right angle.

One of the best collections of wax anatomical models in the world.

An ornate private entrance to the Vienna subway built specifically for the emperor.