Guns that have been defending San Francisco since 1904.

A brooding mansion of clinker brick stands out among the Victorian houses of Pacific Heights.

A famous alternative culture epicenter and where Joplin serenaded young hippies.

This turn of the century masterpiece has a mysterious goaty interloper.

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.

A huge musical instrument played by the ocean.

Aqueducts have dramatically changed this old lake, now home to tufa towers and its very own species of tiny brine shrimp.

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

A working miniature city designed to teach kids about safety and presumably city planning.

This graffiti-covered bridge is the quintessential vision of a place for disillusioned youth to escape the complexities of burgeoning adulthood.

The largest drain hole in the world.

A "gravitational anomaly" located in the redwood forests just outside of Santa Cruz, California.

'Cause the fence start shaking, the earth was quaking.

Over 300 taxidermied animals in a Californian restaurant make for a taxidermist's dream and an animal lover's nightmare.

This rare example of a "tidefall" is a spectacular drop from the cliffs down onto the beach.

The largest permanent Monopoly board makes one of the longest games even bigger.

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

Frank Lloyd Wright died a year before construction on his largest public project even began.

A rough granite monument marks the spot where Europeans first caught sight of the San Francisco Bay.

Another of California's unused Cold War missile defense complexes has become a graffiti gallery.

An "anarchical" no man's land, complete with garbage sculptures and a hobo-run "Landfillian Library."

An art collective teaching the more fiery, metal-y art forms.

A crumbling Beaux Arts monument to the Bay Area's age of rail.