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

A replica of the first public theater built in California.

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

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

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

The world's largest military aircraft cemetery.

A peculiar mansion built by the troubled heir to the Winchester Rifle Company fortune.

San Francisco Bay's ghost town.

Standing in a state of "arrested decay," this ghost town allows for a detailed peek into Gold Rush life in an unusually harsh climate.

Oh, just a motel on the edge of the desert decorated with thousands of clowns conveniently located next to an abandoned graveyard.

A monument celebrating the idea of reaching inaccessible places.

The California capital city once stood 10 feet lower than it does today.

The now-abandoned tunnels were built for the transcontinental railroad on the route where the first wagon train entered California.

Thanks to modern navigational tools we now know that the true prime meridian runs through a park next door.

A 2000-year-old Roman amphitheater lies just below Guildhall Yard.

The haunting ruins of Jack London's dream house.

The handiwork of a underdog clockmaker who solved an impossible problem for an Empire, and forever revolutionized seafaring.

A 1,215-foot tunnel transports pedestrians beneath the River Thames.

Hear the quietest sound from across the dome.

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

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

The Empire Mine is "one of the oldest, largest, deepest, longest and richest gold mines in California."

I Street Bridge is the heaviest swinging center bridge in the United States.

Seven ceramic sculptures are scattered around this California college campus.