One of the most elaborate displays of Jellyfish is on display at the aquarium.

Concrete strongholds stand guard over the Golden Gate.

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

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.

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

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

A man-made island in scenic San Francisco Bay.

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

The graffiti-covered remnants of a former triangulation station are balanced precariously on this California peak.

A burnt orange monolithic dome structure perched on a hillside near Interstate 280.

A New England-style lighthouse along California's beautiful Highway 1 gets a re-do.

Housed in a memorial lighthouse, this museum relays the history of surfing, beginning with the antics of royal Hawaiian teenagers.

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

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.

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

A giant chess set, minus the psychedelic drug trip.

One of the largest free-standing structures ever built, this dirigible hangar is now simply a giant skeleton.

From the Difference Engine to the Cray-1, all under one roof.