Gold Rush ship-turned-hotel buried underneath San Francisco's financial district.

Home to a vast and influential collection of Shakespeareana.

A promotional sun clock on the site of San Francisco's great raceway.

Alleyway plaque commemorating the death of a fictional character in The Maltese Falcon, not far from the author's home.

A man-made island in scenic San Francisco Bay.

The miraculous hydrant that saved the Mission District in 1906.

Golden Gate Park's historic collection of plants.

Gold Rush-era tombstones line the park's paths.

A monument to the love people have for their pets.

Not merely a museum – but a whirring powerhouse that offers a subterranean peek into the heart and soul of cable car operations.

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

The restored and active Victorian-era final resting place of San Francisco.

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

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

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

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

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

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

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

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

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.

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