Commemorating Frankfurt's Jewish community and 11,908 victims of the Holocaust.

St. Peter’s, in Western Germany, has stood as a masterpiece of Romanesque architecture since 1181.

This center in the Rwandan capital supports women’s livelihoods while educating visitors about traditional cooking, craft making, and more.

A bronze statue of Momo, a girl holding a huge ear, sits waiting to listen to anyone who needs it.

An extraordinary mechanical calculator designed by the mathematician and philosopher Gottfried Leibniz.

A massive relic of the communist era of Berlin.

Hilltop monument to the victory of a new nation in the Franco-Prussian War.

London's creepiest cemetery was once the site of dueling magicians and mobs of stake-carrying vampire hunters.

Once a 19th-century brasserie, this McDonald's exterior celebrates Alsatian design and the "King of Beer."

This innocuous-seeming building is actually the remnant of a major wartime brothel.

One of Jeff Koons’s largest sculptures and his first commemorative work.

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

An overlooked marble is the only surviving in-place 18th century example of the measurement that changed how we define distance.

A surrealist timepiece by the artist of melting clocks.

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

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

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

Notorious artist squat renovated into legal studios.

The spiral staircase hidden inside this giant Parisian column was likely built for Catherine de Medici's astrologer.

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

A mechanized clock where a man fights off a dragon, crab, and rooster.

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

This banal Parisian entranceway is not what it seems.

The oldest stone house in Paris was built by its most famous alchemist.