An ancient ossuary in Rouen.

These paved rills bring freshwater into Altstadt and could spell wedding bells for whoever stumbles into the waters.

Located in a heritage building, this Mickey D's is missing its Golden Arches.

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

A large portion of this navigable canal runs under Paris's famed boulevards.

A museum on the history of Paris, including a set of Napoleon's toiletries, Proust's room, and relics of the Revolution.

The first green space constructed on an elevated viaduct.

Dedicated to the art of hunting, with juxtapositions of contemporary art.

This charming cobbled backstreet is the most Instagramable street in Paris, much to the residents' annoyance.

Today this former Nazi concentration camp stands as a poignant memorial to the victims of fascism, and a warning from history.

A monumental golden thumb rises as an iconic homage to Nouveau Réalisme, bold in scale and unapologetic in spirit.

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

The birthplace of Karl Marx is now a museum dedicated to the communist revolutionary's life and work.

The last bastion of Roman presence north of the Alps looms over a German town.

A memorial for a young woman and her ghost, which are claimed to have caused countless deathly shipwrecks.

Tiny castle in the middle of the Rhine made you pay to pass.

A former ironworks that was the first UNESCO industrial site.

This Nazi-built amphitheater was constructed on a sacred mountain site used by various German cults.

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

In this German city center, the streets have no names.

A team of concrete athletes stands in the middle of a traffic circle.