One of the largest caves in the world open to the public.

This Roman monument is surrounded by more recent construction, offering a stark contrast between ancient architecture and the modern urban landscape.

Two stone columns flank the grand Venice square, but there were supposed to be three.

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

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

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

Thousand-year-old Viking runes adorn an ancient Greek lion at the entrance to the Venetian Arsenal.

100 year tradition of fist fights, marked by marble footsteps.

A sinister pyramid in the Frari contains the heart of the famous neoclassical sculptor.

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

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 community on a small Venetian island has taken to painting their houses in bright neon hues.

A haunting collection of sunken wooden barges litters this Italian river bend.

A little sculpture with a large wardrobe.

Classic game cookery takes center stage at what's widely considered London's oldest restaurant.

The colorful stairs are made with marble from the world's major quarries.

This obscure walkway links Edinburgh’s Old Town with one of the city's prime vantage points.

The taxidermy remains of the first mammal ever cloned from an adult cell are on display in Edinburgh.

This 16th-century house tells the city's history through old artifacts and quirky tales.

17th century streets hidden under Edinburgh were once a breeding ground for the black death.

In one of the smallest countries in the world stands an original Salvador Dalí sculpture.

Trek into the depths of the cave where 17,000-year-old paintings exist alongside 400-year-old graffiti.

The most radioactive spot in New York City can also fix your muffler.

A giant sculpture of the legendary "Salmon of Knowledge" celebrates the return of fish to Belfast's River Lagan.