This Dutch art piece became a Russian icon.

Albert Einstein would often sit in this chair during visits to the observatory to discuss science with Willem de Sitter.

This 11th-century castle sits so low you can't see it behind the surrounding buildings.

A trio of red, white, and blue stones embedded in the streets of Leiden are markers of medieval territory and law.

This series of Baroque passageways in Vienna's cultural center mix old architecture with modern art.

The Habsburgs' royal collections of art and wonders.

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

The Bauhaus-style former industrial complex is considered the world's most beautiful coal mine.

An ancient Egyptian temple sits within a modern European museum.

Devious political maneuvering and four ancient, working telescopes are central to the world's second-oldest observatory.

A 'living museum' in Leiden, the oldest of its kind in the Netherlands.

Science meets wall art to highlight the beauty of famous mathematical equations.

This automated sculpture of two men peeing will spell out text messages with their micturition.

Microscopic scenes; some call it novelty, some call it art.

Despite attempts by local police to discourage it, Beatles-inspired graffiti has been a means for artists to air grievances for decades.

This tipsy office building in downtown Prague was originally called “Fred and Ginger.”

Two stunning 17th-century libraries and a cabinet of curiosities.

Macabre astrological automaton clock dating to the late 1400s.

A Jenga-style cylindrical tower of books that appears to go on forever.

Most prolific publishing house in the 1600s open to the public.

An indoor miniature village and labor of love for Laurence Geiringer, a model railroad enthusiast.

A toxic ghost town sitting atop a massive coal fire.

A comic book store got the road by its shop officially renamed after Superman's girlfriend.

The only museum with its curator—and her pets—buried inside.