The crypt of the imposing Stephensdom holds royal intestines and thousands of skeletons.

A tropical paradise just a short trip from the opera house is filled with beautiful winged creatures.

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

Mummified monks and the accidentally interred, in a 17th-century crypt.

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

St. Mary's features one of the most spectacularly decorated cathedral interiors in all of Europe.

This enormous 32-foot painting depicts Poland's greatest medieval battle in glorious detail.

The colonial city's social history is reflected in its fanciful door knockers.

This elegant Colombian fortress was one of the torture headquarters for the Spanish Inquisition.

An ancient city hidden in the heart of the Sierra Nevada mountains.

One of the oldest and largest castles in the world.

This architecturally eclectic fortress witnessed centuries of bloody turmoil, including the massacre of its ruling clan.

The fairy tale castle of the "fairy-tale king."

This magnificent castle grew from a small Moorish fortress, and reportedly inspired two iconic Disney castles.

This fairytale castle was built as a show of power but was nearly torn down thanks to its history of torture.

A castle built for love, and abandoned due to heartbreak.

It might not be the prettiest pyramid in Egypt, but it may be the muddiest.

This ancient structure is widely thought to be the oldest intact pyramid in the world.

A fortified city, home to a remaining population of five families