An Austrian house of bones filled with hundreds of intricately painted skulls.

Baroque celebration of the end of the Great Plague of Vienna.

Op-art architecture designed for happiness.

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

The topiary maze at the Habsburg hunting lodge.

Built to give thanks for the passing of a plague epidemic, this cathedral is a one-of-a-kind architectural hybrid.

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

The final resting place for the remains of 143 Habsburg royalty.

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

The beautiful baroque library of the Hapsburg empire.

This "mathematical tower" was an observatory, early skyscraper, and place to reflect on all of nature and the cosmos.

This curious, round temple is the oldest still-standing marble building in Rome.

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

Rome's semi-secret peephole vista is also a former Crusader stronghold.