Legend says this rock was once a chopping block for public executions.

Stockholm's last remaining paternoster elevator.

Contrary to what its name suggests, you won't find any bunnies here.

This building’s ghostly exterior reflects its former lives as a prison, school, and funeral home.

A subterranean world of tunnels links several buildings of this rare 19th-century asylum.

The first piece of public art dedicated to LGBT rights.

New York City's smallest piece of private property.

A mysterious carving from 17th-century London seemingly depicts a young boy sitting on a bread basket.

This otherwise ordinary close on the Royal Mile constituted the end of the world for Edinburgh’s poorest residents.

This massive underground salt mine now holds a sci-fi theme park in its depths.

Twenty churches beautifully painted by 19th-century Czech and German immigrants in Texas.

A medieval castle in the middle of rural Texas.

This eclectic, mosaic-clad home includes a bamboo ping-pong loft and a "Whispermaphones" intercom.

There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

This collection of neon icons is preserving Arizona's history, one sign at a time.

These tiny statues form a terracotta army from China's Han dynasty.

This neighborhood of futuristic ball houses looks like an alien settlement in a science fiction film.

A giant roundabout made up of six smaller roundabouts can befuddle the uninitiated.

Volcanic stone sentinels stand watch at a Korean Bell Garden in Virginia.

An abandoned amusement park hints at the twisted history of the Newfoundland Railway.

These ruins witnessed the final gathering of the failed Jacobite Rebellion.

The first permanent memorial to a unique secret weapon of World War II.

A 66-million-year-old rock formation stands tall over Mumbai, offering stellar city views.

One of only two pod-shaped homes designed by Frank Lloyd Wright.