An architectural oddity of six stories, accessed by graceful ramps.

A simple plaque on the facade is the only reminder that the treaty ending the American Revolution was signed inside.

Despite centuries of architectural innovation, this French castle is being built like it's the 13th century.

This recessed garden protects thousands of mountain plants by creating its own microclimates.

The construction of a tram line unveiled hidden remnants of the old medieval city.

A mud statue stands in the dark tunnels, seeming to hold up the weight of the city above.

With a history of slaughter, feast, and famine, remnants of the pork industry decorate this area--even its church.

Tables of secondhand books fill the inner courtyard of this 17th-century stock exchange.

This crumbling, graffiti-covered mansion sits tantalizingly within reach of the proletariat who frequent a public park.

Trek into the depths of the cave where 17,000-year-old paintings exist alongside 400-year-old graffiti.

A French library that makes sure its love of books is writ large... giant in fact.

A colossal sculptural lion built by the same man who designed the Statue of Liberty.

These crumbling Nazi artillery bunkers are now fair game for massive graffiti projects.

A quaint medieval millhouse hovers surprisingly above the waters of the Seine.

This ancient theater was once the home of fierce gladiatorial battles.

Former hunting lodge of a duke who was an avid collector of impressionist works.

What looks like a normal building is really a hollow facade hiding a subway vent.

This Parisian gem is one of the most incredible ethnographic museums in the world.

The sunken structure looks like the victim of a catastrophic flood.

The deserted pirate-themed restaurant still entices explorers.

The 16th-century church was kept in its ruined state as a reminder of the casualties of World War I.

A swath of France so devastated by war it is still forbidden to go there.

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

An odd museum dedicated to French fakes.