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

A grotto-like lodge decorated with gilded mosaics, rocks and a noisy waterfall was the setting for the most sumptuous pleasure house of 1900s Europe.

The subterranean "lake" below the Paris opera house inspired the Phantom of the Opera's lair.

Exquisite wall sculptures carved in secret by an early quarryman in an obscure corner of the Paris Catacombs.

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

Behind the pink curtain, Au Bonheur du Jour, an art gallery of erotic archives.

Egyptian Revival movie palace abandoned for decades and restored in 2013.

A museum of magic with a Sadist past.

A favorite Paris bar for U.S. expats, including Gershwin, Hemingway, and James Bond.

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

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

Abandoned railway line circling the city of Paris.

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

The vast, legendary catacombs hold secrets much stranger than stacked bones.