This free, take-a-book shop seems like a trick but isn't.

Home to items never before seen by the public.

Site of a classic 19th-century physics experiment to prove the earth is rotating.

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

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

A layered tribute to the work of mosaicist Isaiah Zagar.

Macabre astrological automaton clock dating to the late 1400s.

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

Thousands of narrow alleyways in an ancient medieval city make up what's believed to be the world's largest car-free urban zone.

The oldest known university in the world is in Fez, Morocco.

Traditional 11th-century outdoor tannery.

The other side is actually green.

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

A Parisian cemetery where the elite and artistic are interred beneath an eccentric collection of tombs.

The celebrated eyesore created by starry-eyed sweethearts.

Founded as a refugee camp, now a popular tourist spot.

A crumbling cathedral condemned by an earthquake.

There must be a pun in this haystack somewhere...

Commemorating the spot where the famous scientist fed his pigeons.

An artist's cute bronze subway sculptures belie his violent artistic past.

This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

Avoid gangster interaction while window-shopping.

Slyly buy a shake in the Parker Meridien lobby.

Mysterious 500-year-old tapestries depict a unicorn hunt.