The eclectic observatory castle of a 19th-century astronomer and explorer.

Abandoned blockhouses from Nazi Germany's Atlantic Wall erode into the sea on a French beach.

The post-apocalyptic remnants of a bucolic town ruined by a plane crash.

One of the last realized projects of an influential, self-taught, French Modernist architect Jacques Couëlle.

Perfume museum and library.

The largest refracting telescope in Europe is housed on the grounds of a former French castle.

The man who introduced reinforced concrete to the world demonstrated its genius by using it to build his own house.

Ghosts of France's colonial past.

In this Parisian garden's grotesque former life as a zoo it fed exotic animals to the bourgeois and put humans on exhibit.

This hidden workshop is filled with molds of France's most iconic sculptures.

Abandoned railway line circling the city of Paris.

Skeletons, medical artifacts, and other obscure and precious treasures all displayed in a wooden pharmacist's cabinet.

Collection of antique taxidermy and natural specimens, near one of Paris's oldest flea markets.

A modern-day Lascaux cave underneath Paris.

The storefront of a ramshackle Parisian puppet theater.

The personal library of the founder of modern neurology is open to visitors.

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

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

Stroll through retro Paris while shopping for old postcards and discarded doll heads.

This Parisian café sticks almost exclusively to an ethos of reuse.

The ruins of a Duke's bucolic dream, where camels once roamed alongside "Dutch" windmills and faux-Italian vineyards.

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

A scandalous Art Nouveau collaboration that set Paris all atwitter at the turn of the century.

The curious underground history of keeping Paris clean.