Medicinal spa created from the mineral-rich runoff of a geothermal power plant

The deepest sinkhole in Central Europe comes with a grisly tale and an unusual nickname: “The Stepmother Abyss.”

Europe's largest natural bridge has a 19th century royal chateau built into its side.

The world's greatest slide descends 18 stories from this looping mountaintop viewing platform.

A spiral staircase twists to the top of this unusual Czech lookout tower.

Heralded as one of the prettiest castles in all of Czechia.

Straight out of a nightmare, barcode-faced babies climb up and down Prague's television tower.

The rusted creatures wait to be discovered in Prague's botanical garden.

Underneath the city that invented pilsners are a series of historic tunnels that have been storing beer for centuries.

One of the oldest, well-preserved water treatment facilities in all of Europe.

An underground city of salt.

The former Nazi Germany concentration camp stands as a museum to remember this dark chapter in European history.

This contentious squat has stood through fire, violence, and government intervention as a hotbed of leftist protest.

Hamburgers are intensely proud of their tunnel beneath the river.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.

A whimsical and twisted animatronic monster tour beneath the streets of Berlin.

Two monstrous faces loom over a village in Czechia.

These delicate sand pyramids look like naturally occurring gothic spires.

Austria's ultra-modern art museum looks like Cthulhu's giant alien heart.

Resting in the middle of an Austrian river, this sci-fi "island" lets people cross in neon style.

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

Swarovski's museum/theme park is a fake diamond fantasia overlooked by a giant.

Enormous sandstone towers loom within a Czech forest.