The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

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

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

Wall Street has a new heroine, a bronze statue of a small but fierce girl.

The magic's in the hole!

A church of bones, decorated with 40,000 human skeletons.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

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

A museum dedicated to the history of a terrifying secret police is now held in their former headquarters.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

Macabre astrological automaton clock dating to the late 1400s.

Its buzzing collection honors vibrator history.

This modest marker near Notre Dame identifies the very center of Paris.

The "Seinfeld" diner.

Relics of the 1894 Midwinter Exposition continue to delight visitors today.

An emporium for the weird, creepy, rare, and just plain gross.

A Jenga-style cylindrical tower of books that appears to go on forever.

Banksy gives themself artistic license with this piece of London street art.

Elevated freight railway turned wildly successful urban park.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

Try not to get slimed in Tribeca.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

These old stone ruins in the Oregon wilderness were once bathrooms and are steeped in legends of murder.

Amid the bustle and noise of the Financial District hides a secluded garden oasis above the city streets.