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

High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

A kindergarten shaped like a cat with a tail that's a slide.

A top-secret bunker now turned museum, is an eerie look at what life would have looked like in the event of nuclear war.

An underground city of ancient quarry tunnels hid thousands of Allied soldiers in WWI.

A mosaic-tiled house built by graveyard sweeper Raymond Isidore.

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

Personal garden filled with mosaics made of recycled garbage.

Folklore and history carved into Brittany's coast.

Massive puppet-automaton machines created by French artist collective Machines de l’Ile.