Berlin's old airport.

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

The most visited, and possibly most controversial, museum in Germany.

This ancient theater was once the home of fierce gladiatorial battles.

This massive monument honors the first human in space.

Gargantuan home of Russian science.

Stalinist skyscraper built with help of cryotechnology.

One of the world's tallest statues is also one of its most hated.

World's largest bell sits on the grounds of the Kremlin in Moscow.

This building holds the embalmed remains of the leader of the Bolshevik Revolution.

The gorgeous entrances into the city's underbelly look more like grand halls than subway stops.

The tallest hotel in Europe.

The deepest metro station in the world.

This demon atop the Notre-Dame de Paris looks utterly bored.

The celebrated eyesore created by starry-eyed sweethearts.

This bridge was constructed from the rubble of the infamous Bastille.

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.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

This charming, narrow-gauge railway in the Thames Estuary is sometimes referred to as the "Train to Nowhere."

Today, Kent's medieval monarchs hold court on a busy pedestrian thoroughfare—or at least their statues do.

This skewed English house has looked like it's going to fall over for centuries.

A defensive structure built during the Hundred Years War has remained useful in one way or another for nearly 700 years.

A giant roundabout made up of six smaller roundabouts can befuddle the uninitiated.