This concrete tangle of square pipes has stood as a proud thorn in the city's side since the '70s.

The remains of a ruined mansion memorialize the 1906 earthquake.

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

In this century-old literary safehouse, print is alive and well.

Big gun installations, built over a massive cemetery, now abandoned & hidden in trees.

A nondescript building that's been functioning as a speakeasy for nearly a century and a half.

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

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

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.

A shop full of natural curiosities, carnivorous plants, and costumed taxidermied mice.

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

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

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

Tiki luxury on Nob Hill.

A favorite haunt of dinosaur loving children and hallucinogen loving hippies alike.

Olfactory delights in San Francisco's Botanical Gardens.

A museum befitting the city responsible for supplying the majority of the world's LSD.

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

The only theatre in the world constructed specifically for sound movement.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

Get lost in this haunting fairytale art walk through a man-made eucalyptus grove.

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

A 140-year-old castle with underground caves hidden in San Francisco.