A silly medieval mural preserved on the side of a Viennese house.

Giant WWII fortresses that fired 8,000 rounds a minute, now home to thousands of pigeons.

Located right outside of Vienna, visitors can take in expansive views of an ethereal forest.

This Austrian museum celebrates the work of famous forgers and their inimitable imitations.

The former private quarters and office of Dr. Sigmund Freud now hosts a museum housing the works of the founding father of psychoanalysis.

Handsomely crafted representations of our round planet.

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

The beautiful baroque library of the Hapsburg empire.

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

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

The final resting place of the poets Shelley and Keats.

Hundreds of lucky felines haunt the ruins where Caesar was murdered.

More sculpture than building, this architecturally significant temple was built on the spot of Saint Peter's crucifixion.

This ritzy Italian market is built around a statue of an unforgiven heretic who was burned for his belief in an endless universe.

A map of Italy made entirely of trees.

The city of Palestrina was built around this magnificent terraced sanctuary dedicated to the pagan goddess Fortuna.

One of seven Jewish catacombs in Rome and one of only two open to the public.

Ancient ruins hidden underneath a modern luxury hotel.

Breathtaking and huge 430 year old maps of Italy.

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

One of several skulls claiming to belong to the beheaded St. John the Baptist is on display at this Roman church.

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

A monument to the man who almost killed Hitler.

A brush maker used his factory to protect blind Jews from the Gestapo.