Prone to disastrous fires, the city of San Francisco has the Guardian, a fireboat gifted by residents, to watch over them from the bay.

One time home to turn of the century explosives, now hidden under the Bay Bridge.

San Francisco's first World's Fair, dedicated to the wonders of California.

The second building of its name to occupy this location might be the finest flatiron building in San Francisco.

A modest reminder of treacherous waters at the Golden Gate.

Only hotel where you can legally launder money.

Guns that have been defending San Francisco since 1904.

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

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

Faceless white figures loom over the city from the rooftop.

A pair of mutilated bronze octopuses slump at the base of the monument honoring California's admission to the U.S.

Over 315,000 preserved amphibians and reptiles in jars.

A man-made island in scenic San Francisco Bay.

Inside an old airplane hangar, friends and strangers alike play on a massive trampoline.

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

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

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

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

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

A pair of slides and a tree-lined stair corridor have been an urban oasis for nearly 40 years.

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

A huge musical instrument played by the ocean.