Over 50 exquisite hand-painted Renaissance maps decorate a Medici storage room.

This private skyway is filled with art and was expanded explicitly so that Hitler could appreciate a river.

The skull of the patron saint of lovers lies in the Basilica di Santa Maria in Cosmedin—maybe.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

The doodles of a genius line the walls of a secret room under the Medici Chapel, where they were hidden for nearly 500 years.

Hidden beneath the famous St. Peter's Basilica is a veritable city of the dead that may hold the remains of St. Peter himself.

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

The yawning maw of this pagan visage is said to bite off the hands of liars.

The final resting place of the great navigator, or maybe his brother.

Amsterdam's former hotspot for public executions and dissections.

A hidden church in a hidden courtyard tells the story of the Miracle of Amsterdam.

Three connected pink triangles memorialize persecuted gays and lesbians throughout history.

This city square is home to Amsterdam's oldest church and a statue honoring Dutch sex workers.

This magnificent museum claims to house the cranium of a disciple and the skull of a pope.

Every hour the doors open to reenact the legend of the heroic mayor who saved his town by drinking a gallon of wine.

Horrifically creative torture devices and shame punishments line the walls of this chilling museum.

This abandoned coliseum was intended to be a grand Nazi rallying ground before it was halted at the end of the war.

A castle from the Holy Roman Empire that hosts traveling youth... in its stables.

The footprint of a frustrated devil in Munich's Cathedral.

Golden cobblestones remember a time when this small alley was used to avoid having to give a Nazi salute.

Among the ostentatious rococo ornamentation of this church, an image of death cuts the life-thread.

The medieval "dragon" on an Austrian city's coat-of-arms comes to life in a fountain.

A wunderkammer of gold and silver reliquaries and ancient saintly bones.

No one is sure if the world's fourth-largest diamond had been found in a rubbish heap or was pawned by Napoleon's mom.