Dating back almost 400 years, the oldest public collection library in the United Kingdom was once the study hall of Karl Marx.

The National Railway Museum in York is the largest railway museum in the world, attracting almost 1 million visitors per year.

One of the shortest streets in York has an especially odd name.

Follow the original medieval paths that wind through this intriguing section of the city.

Beneath the city of Lourdes, France is a massive, concrete church.

An unsettling sculpture of a boy hanging out in a street in Ghent has been baffling visitors for years.

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

This fairytale castle was built as a show of power but was nearly torn down thanks to its history of torture.

Christ's blood allegedly preserved in a Belgian town.

The legendary giant's severed hand sits on Antwerp's popular shopping street.

A man throwing a giant severed hand towers over Antwerp’s main square.

This statue dedicated to the story of a Flemish boy and his dog was relatively obscure in Belgium, but a cult sensation in Japan.

Belgium’s famous peeing statue has worn many hats (and coats, and pants), which are on display at this small museum.

Pompeii's less famous neighbor is still revealing her secrets.

This amazingly well-preserved villa just outside Pompeii boasts rare examples of ancient Roman paintings.

The walls and streets of the ancient city are peppered with penises.

Erotic art covers the walls of the largest ancient pleasure palace.

Ancient snack bar of the Roman Empire re-opened.

The last moments of the ill-fated Pompeiians, frozen forever in plaster.

These "anatomical machines" are only one of the many strange items in this Italian crypt.

The once forbidden "secret cabinet" of erotic art from excavations of Pompeii and Herculaneum.

The remains of this 2nd-century Roman temple are incorporated into a modern building.

This ancient market is often referred to as the oldest shopping mall in the world.

The "Great Sewer" of ancient Rome is one of the oldest sewer systems in the world, and is still in use.