This Hungarian castle was built out of cardboard and wood until it proved so popular that it got upgraded to stone.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

The Habsburgs' royal collections of art and wonders.

Dedicated to the man who saved hundreds of children from Nazi-occupied Czechoslovakia.

A Baroque mansion with ties to legendary magicians and alchemists.

Be(w)ar(e) the moat around this historic Czech castle.

Increasingly decayed figures stand as a powerful reminder of the human costs of Czech Communism.

A turn of the century building boasting some of the most beautiful art nouveau architecture in Prague.

This walkway is so narrow it needs its own light to stop pedestrian traffic jams.

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

The medieval "Bearded Man" relief still serves as a clever flood warning marker.

A surreal statue honoring Prague's favorite literary son.

The palace window through which Protestant nobles flung two Catholic regents, thus sparking the Thirty Years' War.

An existential riddle in the world's largest ancient castle.

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

Macabre astrological automaton clock dating to the late 1400s.

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

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

This small, ingenious cannon once helped regulate Parisian life.

The video game-themed street art first popped up in the French city.

A series of abstract, silly sculptures represent the works of a great modern classical composer.

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.

A mechanized clock where a man fights off a dragon, crab, and rooster.