The former Nazi Germany concentration camp stands as a museum to remember this dark chapter in European history.

This antique farmhouse is one of Læsø's rare seaweed houses.

This stunningly massive housing complex is a go-to filming location for dystopian sci-fi cinema.

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

The unique design of these skyscrapers in a Paris suburb led to them being nicknamed "cloud towers."

The patron of this extravagant Art Nouveau confection insisted that nothing less than a boat should project from its facade.

A suburban housing complex with astonishing architectural features, locally nicknamed "the Camemberts."

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

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

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 curious underground history of keeping Paris clean.

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

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

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

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

Notorious artist squat renovated into legal studios.

This massive library holds what was once the largest book collection in the world.

France's most famous cemetery, with some of its most curious tombs.

A copy of the Statue of Liberty greets visitors to the birthplace of Auguste Bartholdi.

Folklore and history carved into Brittany's coast.

The great Italian Renaissance painter was laid to rest here in the Chapel of Saint-Hubert.

Twelve grave-faced marble angels guard the emperor's tomb at Les Invalides.

This Slovak bridge is known both for its connection to a national uprising and its UFO-shaped eatery.

The largest fountain in Bratislava.