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.

Museum dedicated to the terror regimes of Hungary.

This abandoned Greek island was the last active leper colony in Europe.

A minotaur, a labyrinth, and a dubious restoration pull in visitors from around the world.

A luxury hotel housed in a former 15th century Gothic church.

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

Tables of secondhand books fill the inner courtyard of this 17th-century stock exchange.

The castle was reconstructed to fit Kaiser Wilhelm II's romanticized vision of the Middle Ages.

Thousands of years of crashing waves gave this mushroom-shaped rock its svelte figure.

Pop culture has helped to keep this iconic British building from being destroyed.

One of the highest mountain passes in Europe has been ranked among the best driving roads in the world.

A massive mausoleum towers over the gravestones in a 19th-century Italian "model village."

This abandoned Brutalist treehouse is a hidden architectural relic.

These medieval skyscrapers dominate the skyline of this small Tuscan town.

Tourists often confuse this beautifully ornate former cigarette factory for a mosque.

It has an American Dream Car exhibit, Europe's largest Formula One collection, and many, many mannequins.

From Nazi chemicals to the CIA, this architectural marvel has played a fascinating role in German history.

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

The last bastion of Roman presence north of the Alps looms over a German town.

This abandoned coliseum was intended to be a grand Nazi rallying ground before it was halted at the end of the war.

Enter the cabin of a life-sized Hindenburg replica.

This museum tells the story of lake dwellers from 4000 BC to 850 BC, replete with stilt houses and goats.

This former steel and coal plant is now a neon-lit industrial fantasia.