A cemetery for Slovenian notables also serves as a popular recreation space.

Martin Bricelj Baraga's monolithic sculpture measures the blueness of the sky, and changes color to match it.

This former estate of a fascist leader is now a burnt out ruin leading to a system of secret tunnels.

Once a state-of-the-art tuberculosis treatment spa, these ruins are now ruled by paintball players.

This giant subway sculpture celebrates the fruit that inspired the theory of gravity.

Stockholm's narrowest alley is barely over two feet wide.

This walkway is so narrow it needs its own light to stop pedestrian traffic jams.

A former squatter's paradise outside Prague.

A giant interactive periodic table with real samples of the elements.

This series of Baroque passageways in Vienna's cultural center mix old architecture with modern art.

A wooden street sign is the last remnant of this 400-year-old alleyway.

A series of playful yellow penguins share a serious message about the environment.

An army of sleeping knights sculpted by a self-taught local artist beautifully depict an old Czech legend.

Bullet holes in the church wall are a reminder of the violence that followed the assassination of a high-ranking Nazi officer.

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

Locals say the stone that marks the spot where the gallows once stood can lead you astray.

A crucified and bearded female saint.

A saintly relic hidden in a Prague church basement.

This magnificently macabre shield shows the power of chivalrous love in medieval times.

A gruesome and mysterious ancient sculpture of a pagan deity from the Roman occupation of Celtic Britain.

A perfectly preserved hill village where the buildings are painted like white lace.

Terrifically morbid cemetary and site of famous Paracelsus' grave.

Outside a Viking museum sits a modern-day runestone made by a Swedish runemaster using traditional methods.

This intriguing Bronze Age artifact spent centuries hidden within a Welsh faerie hill.