This mural painted by Keith Haring was done without payment as a gift to entertain the children at the Hôpital Necker.

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

Inside a former cabaret, seven floors of erotic art.

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

A phantasmagoric tomb honors a Belgian artist-scientist's contributions to the world of spooky entertainment.

A haunting collection of the vanished and disappearing natural world.

This structure atop a craggy cliff in one of the most beautiful parks in Paris boasts an unbeatable view.

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

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

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

An iconic and eccentric bar for "Manouche" Jazz music keeps expanding its space—and its influence.