Though its celestial ceiling is impressive, the true star is the vast collection of French books.

The world’s oldest and biggest bookstore stocking only mystery, crime fiction, espionage, and thrillers.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

A sprawling collection of books and manuscripts about ancient Greece that would have put their famed libraries to shame.

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

Perfume museum and library.

A haunting collection of the vanished and disappearing natural world.

The curious underground history of keeping Paris clean.

The macabre collection of Jacques Sirgent, an expert scholar on the undead and all of their trappings.

A counter-culture bookstore like no other hides in plain sight in the streets of Paris.

Statue of death tucked in the University of Medicine courtyard.

The Sun King's military models, saved from the Louvre.

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

One of the oldest medical collections in Europe focusing on rare surgical instruments.

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

Known as the "Dodo Manège," this carousel features a herd of animals that have disappeared—or may be gone soon.

This museum houses an imposing skeleton army comprised of creatures great and small.

This former “ante-chamber to the guillotine” has been refurbished to illustrate the brutal history of French justice.

Notorious artist squat renovated into legal studios.

These broken shards of ancient ruin may hide an ancient pyramid.

The most alien-looking place on Earth.

The ruins of an ancient island city built atop a coral reef in the South Pacific are spectacular and strange enough to have inspired H.P. Lovecraft.