Hidden beneath the famous St. Peter's Basilica is a veritable city of the dead that may hold the remains of St. Peter himself.

This attraction was abandoned after the Chernobyl disaster.

The ghost town left by the worst nuclear disaster of all time is being taken over by nature and urban explorers.

An illuminated manuscript comprising the life's work of a lone monk, inexplicably decorated with a portrait of Satan himself.

This one-time health resort was used by aristocrats around the world.

Stunning examples of Russia's 18th-century wooden architecture.

Palace where the nearly un-killable Rasputin was murdered.

It took over half a century but a Russian monument to a famous and tragic space pup finally stands in Moscow.

A fairytale Gothic castle steeped in Nazi treasure conspiracy theories.

The walls and ceiling of this Polish church are decorated with thousands of skulls, with another 21,000 skeletons just below.

At this Arctic outpost, get to know members of the indigenous Sámi community and meet their herds.

Walk behind a 50-meter-high waterfall.

One of the most breathtaking railways in Europe also takes one of the steepest climbs, from fjord to mountain plateau.

Museum celebrating the ocean, with the largest wunderkammer dedicated to sea exploration.

An old hill fort covered in over 100,000 crosses is a symbol of Lithuanian nationalism and beliefs.

Lithuania's outdoor sculpture trail of wooden folk art.

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

A submerged archeological park still holds the wonders of a Roman Sodom.

An unusual manor of stunning beauty, born out of a crippling disease.

A moody and picturesque riverside ruin overgrown with vegetation.

Dublin's "Dead Zoo" serves as a window to Victorian museum design.

The oldest pub in Ireland may also be the oldest surviving bar in the entire world.

This permanent collection of preserved bodies taken from Irish bogs is one of the leading authorities on such morbid mummies.

Perfectly preserved ancient monastery in an impossibly dramatic location on a rocky island in the Atlantic.