You can spot this teeny tiny stained-glass window from the Bonifacius bridge.

The patron of this extravagant Art Nouveau confection insisted that nothing less than a boat should project from its facade.

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

A 14th-century fortified keep showcases the masterpieces of an ingenious 20th-century clockmaker.

Three floors of musical instruments coming from all corners of the world and hundreds of years of musical history.

This fairytale castle was built as a show of power but was nearly torn down thanks to its history of torture.

Epicurean and holy traditions converge in what may be the oldest restaurant in Europe.

At this exhibit on the world of poison, venomous animals steal the show.

This skeleton-filled altar piece served as a backdrop to one of the most iconic scenes in "The Sound of Music."

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

Double spiral staircases are not unheard of, but they are very rare.

A centuries old castle atop a dormant volcano houses museums devoted to both women and witches.

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.

Trick water gardens from 1619 featuring a 200 piece mechanical theater powered by water.

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

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.

The single richest source of elemental discoveries in the world.

The discovery of an old wall led to the creation of this fascinating museum about the city in the Middle Ages.

An ancient Viking runestone hidden in plain view in Stockholm's old town.

It is said that each of the white stones in the red facade of this medieval house represents the head of a murdered Swedish noble.

This bridge's unique architecture honors nautical heritage and encourages self-awareness.

Bored potato-guarding Nazis etched their thoughts onto a brick storage building in Copenhagen's Meatpacking District.