The taxidermied remains of the "last wild grizzly bear in California" and of the symbol of the state of California.

An elaborate gift from Claus Spreckels is now a piece of San Francisco history.

This giant head is all that remains of a once proud statue that survived an earthquake but not a fall off of a wagon.

Faceless white figures loom over the city from the rooftop.

Forgotten and then destroyed by fire, this was once one of the largest saltwater swimming pools in the world.

Barely visible foundations remain where Stow Lake’s “observatory” once welcomed visitors.

Amazing meticulous gardens of personal wood carvings, Hydrangea, Canna, and many other flowers.

The remains of a 12th-century chapter house in Golden Gate Park.

A man-made island in scenic San Francisco Bay.

The miraculous hydrant that saved the Mission District in 1906.

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

San Franciscans leave gifts and messages for the magical beings that live behind the tiny, mysterious door installed on a tree in Golden Gate Park.

An overlooked and unassuming engineering marvel.

The remains of a ruined mansion memorialize the 1906 earthquake.

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

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

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.

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

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

A psychedelic labyrinth on the San Francisco bay.

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.

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