Museum dedicated to the terror regimes of Hungary.

This Hungarian castle was built out of cardboard and wood until it proved so popular that it got upgraded to stone.

Late at night, the bust of the "Dracula" actor was snuck onto the facade of this Budapest castle.

An overlooked memorial honoring the local Washington residents who died in World War I.

Those with a sharp eye can find the hidden image of a German Shepherd on the memorial's Mural Wall.

Finnish lake, and scene of an infamous murder mystery.

A beautiful Greco-Roman structure houses a well once believed to have healing powers.

A labyrinthine network of chambers with a storied past hides below Edinburgh's South Bridge.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

Built as an anti-fascist tribute, this surreal Yugoslav memorial became an unwelcome symbol after the Croatian war for independence.

A tower marking the spot where Yugoslavia began its resistance against the invading Nazis stands neglected, but not quite forgotten.

Hiding the longest subterranean river known in the world.

Each spring, a dreamlike carpet of bluebells overtakes the forest floor.

The geoglyph once sported a glass bottle eye.

It's possible to walk inside one of the largest Neolithic tombs in Britain.

The only pub in the world surrounded by an ancient stone circle.

Europe's largest prehistoric mound – burial site of a legendary king?

The largest stone circle in the world has ended up bringing up more questions than it has answered.

The gorgeous entrances into the city's underbelly look more like grand halls than subway stops.

One man's exploration of the human form, including the bizarre and delightful "Man Attacked by Babies."

A cathedral resurrected from the ashes of one of Europe's greatest urban fires.

Pigduck of Turku.

These Finnish rapids have been attracting tourists for over a hundred years and are now released with the push of a button.

Fortifications built for a Soviet invasion that never came now sit abandoned in a losing battle against nature.