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

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

This Parisian fountain is a little bit fantasy and a little bit nightclub.

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

A mechanized clock where a man fights off a dragon, crab, and rooster.

Medieval museum built over Roman baths that features famous tapestries of a lady and a unicorn.

What looks like a normal building is really a hollow facade hiding a subway vent.

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.

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

Indents in the pavement are all that remain from a grisly death machine in Paris.

Walk upon the mementos of the dead in this Parisian courtyard paved with medieval tombstones.

A museum of magic with a Sadist past.

France's national museum of scientific and industrial instruments.

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

A majestic lion statue guards this Parisian botanical garden, and feeds on an unsettling item.

Hidden away in a modern library are the remains of one of the 18th century's most celebrated wunderkammers.

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

A grotto-like lodge decorated with gilded mosaics, rocks and a noisy waterfall was the setting for the most sumptuous pleasure house of 1900s Europe.

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

This statue was given to France by the United States to commemorate the centennial of the French Revolution.

A scandalous Art Nouveau collaboration that set Paris all atwitter at the turn of the century.

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

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

A 16th-century fountain marks the site of a lost medieval cemetery once filled with mass graves.