A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

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

Museum preserving torture methods from the past.

Uh, pardon me, ma'am, but I couldn't help noticing that there's a Columbo statue in the middle of Budapest.

Budapest's Communist-era statues, banished to the suburbs.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

This off-beat, quirky communism-themed bar isn't afraid to poke fun at its history.

Museum dedicated to the terror regimes of Hungary.

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

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

This Budapest bar allows drinkers to leave their mark on the walls, floor, and even ceiling.

This former charity hospital for elderly clergy houses some of Seville’s most treasured paintings.

A 16th-century Andalusian palace.

The world's largest wooden structure.

The final resting place of the great navigator, or maybe his brother.

Spanish architects used seized Muslim gravestones to rebuild parts of the fortress.

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

This floating sculpture of ice is a poignant reminder of nature's power.

The design of this beautifully crafted building was inspired by Norwegian glaciers.

Two stone columns flank the grand Venice square, but there were supposed to be three.

Go inside to really appreciate this 500-year-old technological masterpiece.

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

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

Monument to a suicide protesting the Soviet invasion.