Rome's semi-secret peephole vista is also a former Crusader stronghold.

The subterranean "lake" below the Paris opera house inspired the Phantom of the Opera's lair.

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.

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.

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

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

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

A museum of carnival attractions where you are invited to ride the rides.

Notorious artist squat renovated into legal studios.

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

France's most famous cemetery, with some of its most curious tombs.

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

The fifth tallest statue in the United States is a shirtless monument to the oil worker.

The oldest continuously operating Catholic school west of the Mississippi.

Twenty-seven massive radio antennas on the high plains of New Mexico search for life on other planets.

This simple frog painting created by musician Daniel Johnston embodies the spirit of Austin.

Modern technology and live displays tell the story of the Pacific during WWII for the Internet generation.

The saga of the massive nut begins and ends in Texas.

Two small markers remember the Alamo's feline protectors.

A Saint Nicholas-themed ghost town in the Mojave desert.

Hidden in a hotel parking lot is a strange historical plaque erected by an obscure fraternal society.

Soldiers honored the beloved Pat with a special grave.

These banned cigarette vending machines now sell little pieces of pocket-sized art.