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

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.

A hidden subterranean installation offers a view of the sky.

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

The oldest burial ground in the city, final resting place of city founders, Ohlone natives and murderers alike.

Nestled in the heart of San Francisco’s bustling Financial District stands a unique homage to the Mayan and Beaux Arts.

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

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

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

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

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

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

A collection of 20th-century automata, penny arcade games, and musical contraptions.

Tiki luxury on Nob Hill.

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.

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

Its buzzing collection honors vibrator history.

Carnivorous plants, medieval aphrodisiacs, and the largest original wood structure glass conservatory in the western hemisphere.

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

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

Rodin's famous depiction of Dante's 'Inferno', amidst a sculpture garden of many of his other works.

Successful artist residence program has filled this ranch with dozens of sculptures over the years.