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

Hidden inside a gift shop that doubles as a museum, this gargantuan yo-yo can only be operated by crane.

A sparse, solitary sequoia still stands as a living tribute to the famous conservationist who planted it—but it's dying.

The White House Situation Room was taken apart in 2006 and shipped to the Ronald Reagan Presidential Library.

Centuries of crashing waves carved out this small hole in the rock, which lights up at certain parts of the year.

This municipal playground was co-created by the father of one of the most playful characters ever.

San Francisco's first World's Fair, dedicated to the wonders of California.

One of the only known surviving coconut palm trees in the entire state.

A modest reminder of treacherous waters at the Golden Gate.

The world's largest outdoor organ is played weekly by one of just two civic organists in the U.S.

This rock formation named for its unique shape is one of many that call the Alabama Hills home.

A massive volcanic plug is now a protected area that hosts a number of bird species.

A remote desert lookout offers unparalleled views of the California badlands for those who brave the trek.

The classic Atari game's iconic aliens have invaded downtown San Diego.

Thirteen trees representing the original thirteen colonies were planted with soil from historic Revolutionary battlefields.

At this deceptively beautiful beach, nothing is what it seems.

A monumental cross hides in the trees in Golden Gate Park.

A humble garage, world-famous for being the epicenter of a technology revolution.

Where NASA's satellites and rovers phone home.

The Los Angeles flood disaster that took 400 lives and ended the career of William Mulholland.

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

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

A celebration of once forgotten materials.

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