A walk-in working camera obscura produces 360-degree live images of the San Francisco coast.

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

A modern frieze of ancient Grecian mythological figures playing a national pastime.

These WWII-era murals were initially booed as a libelous portrayal of the American dream but have survived multiple attempts to have them destroyed.

A classic advertising icon immortalized in regal bronze.

The original place where water met land in the City by the Bay is outlined in brass.

Visible below the waves are memorials to the city's Gold Rush dead.

The randomness of this wall of lava lamps helps encrypt up to 10 percent of the internet.

A trash dump made beautiful by nature's power.

The only standing town in the United States that early Chinese Americans built for themselves.

A four paneled, brightly multicolored mosaic adorns the side of this popular grocery store.

Built in 1906, this unique building was the first Hindu temple in the United States.

Once the fastest ship from San Francisco to Tahiti, the Galilee now lays in pieces in three different cities.

27-room home built with the fortune of a sugar magnate.

One of few lasting examples of the brief octagon craze that developed into folly.

A brooding mansion of clinker brick stands out among the Victorian houses of Pacific Heights.

Since 1973, this block has been home to the most concentrated collection of murals in San Francisco.

Its buzzing collection honors vibrator history.

Relics of the 1894 Midwinter Exposition continue to delight visitors today.

A modern mechanical planetary system, part of a 10,000 year clock.

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.

One of the smallest parks in San Francisco honors the legacy of the "Mother of Civil Rights in California."

This sailor's boneyard was lost under a parking lot for decades before being rediscovered.