Concrete strongholds stand guard over the Golden Gate.

A 1920s speakeasy that had rum runners racing up and down the shores of California.

Neither Spanish settlers nor anyone since has been able to tell who built these strange California rock walls.

Once strictly off-limits, this lower level housing curious and priceless vehicles of the Petersen Automotive Museum is now open to the public.

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

Radioactivity still cause for concern at this urban explorer's paradise.

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

Tiki luxury on Nob Hill.

The peaceful gravesite of a rugged wild west gunman echoes the touching story of his last days.

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

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

A sudden forest of traditional Papua New Guinean art works is hidden in a corner of Stanford University.

High on a hill overlooking Los Angeles lives a world famous, high power conical Tesla Coil.

The world's first permanently occupied mountain-top observatory continues to report on the stars.

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

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

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

If you are looking for a used Russian battery, Chinese Ham Radio or other electronic oddities this Flea Market is a good place to start.

An extensive collection of ancient Egyptian artifacts and mummies.

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

An ominous concrete cube cuts a dystopian silhouette atop this California mountain.

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