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

On a winding Vienna side street, one museum has turned their windows into a monument to history’s peace-minded heroes.

Located in a veterinary school, this macabre exhibit displays the effects of animal diseases.

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

A glimpse into the festive and private lives of medieval Europe.

A neo-Gothic mansion now houses a wunderkammer of analog tech that hits on all the senses.

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

A small museum filled with over 1,000 clocks, and one particular clock calibrated to run until the year 9999.

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

This Netherlands museum holds a gloriously mechanical collection of ornate musical automata.

This centuries-old gothic monster has been converted into a sprawling, glossy bookstore.

Birthplace of the "Cat in the Cradle" and a cluster of iconic, original windmills that let the Dutch tame the seas.

Peek through a transparent pyramid and drink in the mountain made of books.

The attic of a four-century-old canal house hides a clandestine church.

This cheese shop also houses a museum devoted to Dutch dairy.

Seven mini rowhouses fill the gap between 54 and 70 Westerstraat.

An ancient passage filled with stalls selling used books, once frequented by Vincent Van Gogh.

The world's first zoo for microbes collecting the horrible and wonderful things living on and around us.

The world's only museum devoted to the wonders of fluorescence.

Tucked in the back of a flower shop, its collection details the fascinating history of the Netherlands's iconic symbol.

A floating cat sanctuary on an Amsterdam canal.

Nature is slowly overtaking this disused cemetery on the outskirts of Brussels.

This collection of over 50 murals celebrates Brussels' rich history as the self-proclaimed home of the "comic strip."

This recently restored crypt was once plagued by liquefying coffins and exploding caskets.