A floating cat sanctuary on an Amsterdam canal.

Museum preserving torture methods from the past.

The most visited, and possibly most controversial, museum in Germany.

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

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

This strange bovine gargoyle is said to have been put in as a passive aggressive form of revenge.

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

A dismembered holy head stares out from her beautiful reliquary at the St. Dominic Basilica.

Renaissance hospital featuring a rotating door into which unwanted babies were dropped.

A large grotto built in the 16th century amidst Florence's famous Boboli gardens.

The famous sculptor left his mark on this Italian wall in an internationally protected example of street art.

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

A neo-Gothic church built to thank God for saving the Emperor of Austria from an assassination.

Beautiful Austrian natural history museum with carved ceilings and row after row of ancient taxidermy.

Handsomely crafted representations of our round planet.

The beautiful baroque library of the Hapsburg empire.

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

An exquisite Baroque church in Vienna's old town.

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

The solemn exterior conceals an opulent interior of this 17th century church.

Legends surround an ancient tree trunk riddled with nails for good luck.

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

The anatomical-pathological collection of a man who changed surgery.

Abandoned substation turned village treasure.