The only monument to name all of the passengers and crew who died on the RMS Titanic.

These barriers stand as stark reminders of Northern Ireland's troubled past.

This massive monument has been telling the time for 150 years—at a slight angle.

A palatial former bank building now houses what may be the poshest art venue (and former Tesco) in Belfast.

This poignant art installation raises awareness of violence against women.

An ossuary built in 1210 to collect bones from the Ospedale Maggiore of Milan.

Two very green residential towers cleaning the air in one of Europe's most polluted cities.

The celebrated eyesore created by starry-eyed sweethearts.

The industrial architecture honors the laborers who brought the Exposition Universelle of 1900 to life.

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.

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

A modern-day Lascaux cave underneath Paris.

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

A Parisian exterminator's shop whose storefront displays stuffed rats hanging from traps.

A Parisian cemetery where the elite and artistic are interred beneath an eccentric collection of tombs.

Site of a classic 19th-century physics experiment to prove the earth is rotating.

A surrealist timepiece by the artist of melting clocks.

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

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

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

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

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.