Paris' linguistic guide to the international language of, yes, love.

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

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

The vast, legendary catacombs hold secrets much stranger than stacked bones.

Exquisite wall sculptures carved in secret by an early quarryman in an obscure corner of the Paris Catacombs.

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

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

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

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

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

These official units of measurement—including chains and perches—lie hidden beneath tourists' feet in a popular London hub.

Once designed as the entrance to Buckingham Palace, this structure was later relocated and stands as a victory arch.

This once-controversial and slightly confusing statue of Achilles was built out of captured cannons.

A statue of the legendary Celtic warrior queen who fought the Roman invaders stands in one of the cities she once destroyed.

The bronze uniforms commemorate the vital role of women during World War II.

One of America's founding fathers lived in this London lodging between 1757 and 1775.

London's smallest police station is barely the size of a phone booth.

The medieval woodcut-style artwork chronicles life in medieval London.

This third-generation institution is one of the last in London that still cures its own salt beef for epic sandwiches.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

Tucked away in the Tower of London is the weapon once used to execute high-profile prisoners.

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.

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

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