Architecture

A spring-fed pool so deep it's used for scuba diving as well as swimming.

The world's second-largest sundial, made entirely out of stone.

This one-of-a-kind archeological site is home to strange prehistoric ruins, the original use of which is still a mystery.

A 14th century bridge built as a fortress, where the devil lurks on one of its towers.

An industrial relic is now one of Europe's most staggering art spaces.

A gravity-defying "devil's bridge" that has a surprising architectural feature for its stability.

Scotland's oldest medieval bridge is also among the last reminders of early medieval Aberdeen.

Once considered the height of medical modernity, this structure is now the oldest remaining component of Roosevelt Hospital.

An indigenous take on European design creates a stunning visual overload.

This derelict building used to house infirm Freemasons, their widows, and orphans.

A Collegiate Gothic quadrangle that surrounds an 18th century secondary school whose financing came from the likes of Alexander Hamilton and Aaron Burr, among others.

A Manhattan office building is home to the world’s largest chess board.

On the top floor of an upscale department store stands a lavish restaurant housed in a replica of a luxury French dining car.

Small monoliths of several varieties of stone sit alongside a wooded path in the Bronx.

This massive stained-glass masterpiece is thought to be the largest Tiffany dome in existence.

A complex of six forts embedded in the Rajasthan hills.

A WWI fighter plane and turn-of-the-century penny candy shop are among the unexpected features of this Financial District building.