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

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

Historic medieval fortified city in southwest France.

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

The tradition of open-air secondhand and antiquarian bookselling in Paris dates back to the Renaissance.

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

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

This charming cobbled backstreet is the most Instagramable street in Paris, much to the residents' annoyance.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

The body of at least one victim of a construction accident was left behind in the collapsed pylon, buried under tons of concrete.

This futuristic German television spire is actually the world's largest digital clock.

The 1852 novel "Uncle Tom's Cabin" lends its name to a subway station, a street, and several shops on the edge of Berlin.

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

Twisted buildings adorn the banks of the Rhine river.

Thousands of tourists and residents in Cologne affix "love padlocks" on the Hohenzollernbrücke Bridge to symbolize their affections.

This painted Lego bridge is the product of over a century of locomotive history.

A monument to the three wars that led to German unification towers within a Berlin traffic circle.

A restaurant and observation deck built in a unique broadcasting antenna.

Berlin's old airport.

This "floating railway" is one of the world's oldest monorail systems.

Where once there was a train station bathroom, there is now this German burger joint.

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

A narrow passage next to a cafe leads to a courtyard exploding with murals, tags, and paste-ups.

A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.