A life-sized mammoth sculpture marks the spot where the remains of a Columbian mammoth were discovered in 2005.

The headquarters of a secretive order is also a beautifully-designed park.

It is locally loved and ridiculed for literally looking like poop.

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

A giant chess set, minus the psychedelic drug trip.

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

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.

An Aladdin's cave of old Silicon Valley tech.

A Roman-inspired temple once controlled half of San Francisco's waters.

San Francisco Bay's ghost town.

From the sky, a kaleidoscope of color brightens the grey landscape of the San Francisco Bay.

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

The old Niles Canyon Aqueduct in the San Francisco Bay Area is a bemusing and secret trail through nature for wayward travelers.

Home to one of the world’s largest collections of model yachts.

The rustic cabin-like decor of this Arts and Crafts-style church reflects the love of nature central to its little-known theology.

A modest reminder of treacherous waters at the Golden Gate.

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

Art in the form of a winding, man made crack in stone.

Guns that have been defending San Francisco since 1904.

The key to turning shifting dunes into the green oasis of Golden Gate Park.

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

Over 315,000 preserved amphibians and reptiles in jars.

Gold Rush ship-turned-hotel buried underneath San Francisco's financial district.