A wall of chewing gum moonlights as collective art.

This working class sculpture pounds his hammer all the livelong day.

This whimsical statue dumps water on its head to symbolize knowledge flowing into his brain. Or maybe booze.

From the sky, a kaleidoscope of color brightens the grey landscape of the San Francisco Bay.

Ninety feet off the valley floor is an ancient dwelling put under protection of the U.S. government by Teddy Roosevelt.

This narrow Ghent alleyway is an officially sanctioned street art tunnel.

This collection of over 50 murals celebrates Brussels' rich history as the self-proclaimed home of the "comic strip."

Three floors of musical instruments coming from all corners of the world and hundreds of years of musical history.

A little sculpture with a large wardrobe.

This whimsical group of statues is a favorite of children who love to climb all over Lewis Carroll's beloved characters.

This sculpture by artist Fritz Keonig survived the 9/11 attacks and now stands as a monument to the victims.

Swarms of butterflies cannot compare to the awe inspired by the publicly-funded nakedness once displayed in this sunken garden.

This little blue house pokes out over the campus of UC San Diego, seven stories high.

This private residence was the template for one of the most beloved television homes of all time.

San Francisco's newly reopened hands-on science museum.

Worker-owned cooperative and resource for those looking to lighten their ecological footprint.

Where the alchemists dream of transmuting base metal into gold was actually achieved.

The Laureates here get something even more coveted than a Nobel Prize: free parking for life.

Now a museum, this building was once a 14th-century monastery and the place where the founder of the Dutch nation lived and was assassinated.

A former poultry store that looks like a giant duck and is one of the "seven wonders" of Long Island.

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

Elevated freight railway turned wildly successful urban park.

This subtle Berkeley paving stone actually marks off a lawless tube of air that extends into space.

The century-old bell and clock tower at UC Berkeley is the third-tallest in the world, and has fossils.