This one-block alleyway is stuffed with street art that is colorful, cultural, and intensely political.

A famous alternative culture epicenter and where Joplin serenaded young hippies.

A man-made island in scenic San Francisco Bay.

San Francisco's oldest surviving monument and meeting place for 1906 survivors.

A collection of memorabilia from the Beat era in the back of a San Francisco bookstore.

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

San Francisco's urban bison herd has persisted in the face of extinction, development, and disease.

A 300-ship graveyard, with a few still visible at low tide.

The one-time watch house for incoming ships at the Golden Gate now stands abandoned and hidden in trees.

Staircase winds down the side of Telegraph Hill through gardens, wild parrots flying overhead.

The seawater playground of gilded-era San Francisco burned to the ground in 1966.

A pair of slides and a tree-lined stair corridor have been an urban oasis for nearly 40 years.

A tiny theater hidden in an alley plays a constant stream of short silent films for anyone willing to peer through the peephole.

Bring your own cardboard to the slippery slopes of concrete hidden in a neighborhood park.

An artsy hidden staircase leads to breathtaking views of San Francisco.

You've probably seen these distinctive orange-tiled columns on the big screen.

Cold war icon and onetime "hole" in the iron curtain.

Named after a militant urban guerilla, this famous former squat is a graffiti-covered stronghold of leftist culture.

A narrow passage next to a cafe leads to a courtyard exploding with murals, tags, and paste-ups.

Once the tallest building in the world, this abandoned church is now a monument to the destruction of WWII.

This contentious squat has stood through fire, violence, and government intervention as a hotbed of leftist protest.

Hamburg's first legal sex work is relegated to a gated street that still does not allow pedestrian women.

Hidden in plain sight on a gable between two towers on the roof of shipping firm F. Laeisz' headquarter in Hamburg sits an unexpected bronze sculpture.

An all-American grocery store in Paris sells U.S. "cuisine" like Pop-Tarts and Heinz ketchup to homesick ex-pats.