Beneath the southern end of the Golden Gate Bridge is the “Gibraltar of the West Coast,” a fort built to protect the San Francisco Bay from naval attack.

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

A man-made island in scenic San Francisco Bay.

The miraculous hydrant that saved the Mission District in 1906.

This shop and studio is dedicated to the art of the book, from letterpress to bookbinding.

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

A 300-ship graveyard, with a few still visible at low tide.

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

An essential stop before plundering, BYO Cutlass.

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

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

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

Concrete strongholds stand guard over the Golden Gate.

The world's most famous donkey lives in this pen.

Guarded by the Angel of Grief, the Stanford family tomb attracts an odd mix of halloween revelry and somber contemplation.

This small monument to the great inventor contains a time capsule and a Wi-Fi hotspot.

A humble garage, world-famous for being the epicenter of a technology revolution.

This odd California folly seems like it was almost designed to accumulate urban legends.

A hidden world of exotic succulents and cacti.

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

Once a welcome symbol for maritime travelers entering Edrom.

This former convent has been reimagined as a community center for artists.

This sculpture was designed to encourage viewers to be true to themselves.

This outdoor museum harkens back to the height of the gold rush.