These caves secretly held national treasures during World War II.

The ruins of an ancient mansion sits in front of and underneath a contemporary art gallery.

An immersive projection art installation uses sound, scale, and light to take visitors inside classic works of art.

One of Whitby's first homes is now a showcase of the lifestyle of early Canadian families.

This 14th century wine cellar is home to the oldest barrel-stored wine in the world.

A museum dedicated to one of Paris’s most famous residents, tucked into a corner of one of the city’s most famous squares.

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

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

Down a cobblestone alleyway is a museum dedicated to Romanticism, with a secret garden.

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

19th century pendulum and a clock restored by a rogue group of guerilla artists.

"In the Dark" Restaurant in Paris offers dinner in complete darkness.

France's national museum of scientific and industrial instruments.

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

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

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