One of New York's best collections of pinball is hidden in a secret bar in the back of this laundromat.

According to the legend, this structure was built in a single night with the help of the devil.

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

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

Italy's curious field of mud volcanoes is named for being both gross AND salty.

Sitting on an Italian hilltop is this surreal fortress built by the mad inventor of electrohomeopathy.

As can be expected from a centuries old church built in a canal city, the undercroft of this house of worship is beautifully flooded.

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

A massive marble foot is tucked away in a small alley near the Pantheon.

This hidden Art Nouveau courtyard is an opulent feast for the eyes.

A factory director designed what was the world's longest suspension footbridge in 1923 so his employees could get to work safely.

Where Venice's gondolas go for a tune-up.

This Roman statue is missing a limb from when the Venetians stole it from Constantinople during the Crusades.

The only museum with its curator—and her pets—buried inside.

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

Venice's "Island of the Mad."

Overlooked amid the tourist bustle of Florence, this museum is dedicated to the craft of stone inlay.

Drink wine handed out through a window as part of an age-old tradition.

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

The famous sculptor left his mark on this Italian wall in an internationally protected example of street art.

This hydrochronometer was invented by a Dominican monk and is a prime feature in this garden.

A forgotten "city of water" underneath the famous Trevi district.

Ancient ruins hidden underneath a modern luxury hotel.

Inside this McDonald's you can dine on your Big Mac and fries next to a 2,500-year-old Roman wall.