This incredible collection of vintage pinball machines can be played at 25 cents a pop.

A huge musical instrument played by the ocean.

The one-time watch house for incoming ships at the Golden Gate now stands abandoned and hidden in trees.

A winding path built in secret on the edge of the continent.

The remains of a ruined mansion memorialize the 1906 earthquake.

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

The sea once considered an ecological wasteland is now called "crown jewel of avian biodiversity" by scientists.

An outdoor sculpture park of giant pink robots and post-apocalyptic Christmas scenes.

"The Hoppiest Place in the World" holds the world’s largest collection of bunny memorabilia and is a singular testament of a couple's devotion to all things Leporidae.

The ghostly remains of an accidental sea.

This large collection of tiny things revels in the art of fine machinery well made.

This strange seaside tower got its name from a wealthy eccentric who would hide coins among its stones.

A walk-in working camera obscura produces 360-degree live images of the San Francisco coast.

Law-protected wreckage serves as a peculiar memorial for an almost forgotten World War II tragedy.

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

A free, public museum dedicated to the fascinating science of sight.

A modern mechanical planetary system, part of a 10,000 year clock.

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

A large instrument played by the wind.

The only theatre in the world constructed specifically for sound movement.

In the days before HD projectors and IMAX, some of the most powerful projectors belonged to planetariums.

Experience a quartz crystal sound bath inside a storied, all-wood sound-chamber.

Explore 10 acres of environmental sculptures.

Located on 420 acres in the high desert, this spiritual center is dedicated to the "science of the future."