Europe's second largest ossuary wasn't discovered until 2001.

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

When a medieval fire claimed the original St. Stephen’s Cathedral, it sparked a pattern of unquenchable organ building.

This network of conjoined cellars was riddled with traps and supposedly allowed the townspeople to pretend their homes were deserted.

Money made from smuggling sugar helped create this wondrous rock maze in honor of the Prussian Queen Louise.

This 8th-century Bavarian monastery is home to an exquisite Baroque-era library.

A pyramid in Central Europe of unknown origin.

This centuries-old wooden wonder was built in less than a year and is one of Europe's largest timber-framed churches.

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

The largest brick bridge in the world.

An officers prison camp believed to be impregnable by the Germans saw over 30 successful escapes.

This jaw-dropping 19th-century bridge uses its reflection to form what appears to be a perfect circle.

A fairytale Gothic castle steeped in Nazi treasure conspiracy theories.

Skeletons dressed in extravagant 18th century royal costumes cavort in the aisles of this German basilica.

Be(w)ar(e) the moat around this historic Czech castle.

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

Enormous sandstone towers loom within a Czech forest.

Slaughterhouse Five opens its dank doors to fans of Kurt Vonnegut.

The sanctuary holds what was once believed to be the saint's incorruptible tongue.

This Dresden church was purposely rebuilt Protestant after being demolished in World War II.

A mansion where wonders of Christmas are celebrated all year long.

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

Before serving as James Bond's Casino Royale, this Victorian-era spa catered to the world's elite.

Visitors flock to the historic birthplace of radiobalneology for its therapeutic radium treatments.