This water-tower-turned-high-end-apartment building was once the site of an early Nazi concentration camp.

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

A 12th-century fortress containing some of Berlin's oldest buildings.

A tree-like building perches on its trunk in the Steglitz neighborhood of Berlin.

The site of the famous Nazi book burning campaign of 1933 remembers its "Night of Shame".

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

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

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

The largest free-standing aquarium in the world resides in a hotel lobby in Berlin.

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

The celebrated eyesore created by starry-eyed sweethearts.

This triumphal arch celebrating the Sun King's conquest of Lille is a masterpiece of military architecture.

This statue honors the thousands of Allied avians that served and died for France during World War I.

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

The narrowest street in Paris.

A 400-year-old church covered floor to ceiling in ex-voto offerings from the faithful.

Ordinary art transforms to extraordinary thanks to locals' quirky sense of humor.

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

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

A 16th-century fountain marks the site of a lost medieval cemetery once filled with mass graves.

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.

This life-size replica of the Statue of Liberty's flame is also a tribute to Princess Diana by default.

Natural history museum celebrating biodiversity with a parade of taxidermy animals.

This surreal statue brings a famous French novel about a supernatural cad to arresting life.