The 28-foot granite map plots the locations of 40 theaters in New York City.

The fanciest public restroom in New York City boasts fresh flowers, art, and a classical music soundtrack.

An uber-secure, windowless tower of doom in the center of Manhattan is an NSA spyscraper.

A pedestrian island in the middle of world-famous Times Square emits a strange (and purposeful) humming noise.

La Cara del Indio honors the Taíno chief who fought bravely against the Spanish invasion of Puerto Rico.

The abandoned remains of this once-thriving hotel looms over the city, awaiting an uncertain future.

Legend tells how a Spanish soldier disappeared from this isolated sentry box without a trace.

This tiny home was originally a narrow alleyway.

This bleach-white graveyard overlooking the ocean is accessed through a tunnel.

This half-finished "city of toys" was almost Italy's own Las Vegas.

This bustling Italian plaza is built on the ruins of an ancient Roman amphitheater.

Fortified medieval tower house with lovely roof garden.

This deconsecrated church has seen many uses, from a tobacco storehouse to a cinema.

According to tradition this is the oldest church in Venice, but its actual age is a mystery.

In the past, Renaissance sex workers were encouraged to entice customers on this bridge.

Those who own or stay at this 500-year-old, allegedly cursed house often meet terrible fates.

This palatial spiral staircase was so unusual the name "snail" was given to the noble family who built it.

Go inside to really appreciate this 500-year-old technological masterpiece.

Venice's "Island of the Mad."

This Venice bookstore has resigned itself to constant flooding by keeping its books in bathtubs and boats.

A fake medieval village in the middle of Turin.

Now an entertainment complex, the Lingotto building was once an avant-garde auto factory with a test track on the roof.

A copy of the famous statue can be found in this Florence piazza, along with one of the most breathtaking views of the city below.

This private skyway is filled with art and was expanded explicitly so that Hitler could appreciate a river.