The world's smallest drawbridge.

An Aladdin's cave of old Silicon Valley tech.

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

This controversial depiction of the "Founder of California" looks as though it was sculpted from mashed potatoes.

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

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

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

This concrete tangle of square pipes has stood as a proud thorn in the city's side since the '70s.

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

Deco Modern sculptures of the people of the Pacific, cast for the 1939 Golden Gate International Exposition.

An enormous artwork that colorfully celebrates over 150 years of US military achievements.

This old-world mansion with lush gardens is a gem in the heart of Silicon Valley.

Condemned US Navy seaplane control tower turned officers’ club sits atop Yerba Buena Island.

After serving in World War II and picking up Apollo astronauts, this aircraft carrier has been turned into a museum overlooking the San Francisco Bay.

A decommissioned Naval base now rents itself out for people who want to blow stuff up.

A private home built to resemble the shape of a microscopic creature.

This (occupied) house is 10 feet wide and full of spite.

The oldest lighthouse on America's west coast no longer needs keepers, yet they maintain the site anyhow.

Every year, over 25,000 monarchs overwinter in Pacific Grove.

A small metropolis of Pueblo cave dwellings have been carved right into the hillside of this national monument.

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

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

When life gave this firefighter a forest fire, he made a rough-hewn sculpture park using a chainsaw.

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