A tiny piece of the Moon is embedded in this stained glass masterpiece.

A historic neighborhood church is reborn as a psychedelic arts collective.

Long-abandoned trolley tunnels just a mile away from the White House are turning into an art space.

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.

The first green space constructed on an elevated viaduct.

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

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

This whimsical castle of grottoes was the labor of love of a French postman, and one of the greatest achievements of outsider architecture.

Statue of death tucked in the University of Medicine courtyard.

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

A museum on the history of Paris, including a set of Napoleon's toiletries, Proust's room, and relics of the Revolution.

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

A surrealist timepiece by the artist of melting clocks.

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

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

This Parisian café sticks almost exclusively to an ethos of reuse.

The very center of Paris is surrounded by a bevy of strange good luck rituals.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

This charming cobbled backstreet is the most Instagramable street in Paris, much to the residents' annoyance.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

Abandoned railway line circling the city of Paris.

The ancient heart of Tunis is an enormous maze of narrow streets and alleyways.

The most alien-looking place on Earth.

The world's largest bioluminescent area was undiscovered by science until 2005.