Today's aerospace industry can be traced back to one man and his gliders.

A plaque outside the San Jose airport commemorates the insect's arrival to the West Coast.

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

It took years to decode its mysterious messages.

At night, this glittering musical tunnel draws skaters and photographers.

Three plaques mark the spot where the "forgotten father of broadcasting" worked.

Anyone can control this glittery light installation with just a phone call.

Eight huge lanterns lining a city street can change color on command.

A lonely monument to the original Silicon Valley tech campus.

The world's most famous donkey lives in this pen.

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

This airfield played a key role in both World War II and the Cold War.

A bronze tribute to a legendary Californian, the self-proclaimed "Emperor of the United States."

Outside San Francisco lies a small clown cemetery and memorial.

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

The final resting place of the Emperor of the United States and Protector of Mexico.

A vast city of the dead, where the deceased outnumber the living by more than a million.

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

A working model of the entire San Francisco Bay and much of the Sacramento River Delta, complete with regular tides that change every 14 minutes.

Visible below the waves are memorials to the city's Gold Rush dead.

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

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

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

A shining, cold, black organ lies in San Francisco's financial district.