This modest marker near Notre Dame identifies the very center of Paris.

The narrowest street in Paris.

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

This 400-year-old tree is actually an immigrant from North America.

Notorious artist squat renovated into legal studios.

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

A beautiful Victorian statue shows France's enduring love of the rhinoceros.

This emotive sculpture was originally created for the 1878 World's Fair.

The celebrated eyesore created by starry-eyed sweethearts.

A glamorous hotel that once accommodated French resistance fighters and concentration camp survivors.

The recovered bones of martyrs slaughtered during The Terror are on display in this church crypt.

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

A scandalous Art Nouveau collaboration that set Paris all atwitter at the turn of the 20th century.

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

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

This off-limits room in the National Library of France is home to a system of pneumatic tubes, once used to bring books to readers.

The curios of pharmacist and collector Henry Wellcome.

A 300-year-old tea shop that brought tea to the English people, not to mention the Queen herself.

These wire animal sculptures commemorate the exotic inhabitants that once called the Tower of London home.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

A mysterious suspended hand greets unsuspecting visitors at the Tower of London.

London's old-school healing garden.

Two copies of a rejected Victorian-era lamp design still stand along the Thames River.

Chelsea's soldiers were given strict orders when crossing this historic bridge.