An art collective teaching the more fiery, metal-y art forms.

San Franciscans leave gifts and messages for the magical beings that live behind the tiny, mysterious door installed on a tree in Golden Gate Park.

A miniature view of the park, caught in time.

Wild West history in Hollywood style.

These subterranean storage areas hold emergency water reserves.

Guns that have been defending San Francisco since 1904.

A three-story, three-dimensional hobo clown in a tutu welcomes CVS shoppers.

A monthly street "service" of handmade puppets and live original puppets, whose devotees profess has the power to change lives.

Concrete strongholds stand guard over the Golden Gate.

The first life claimed by this record-breaking peak wasn't lost to exposure or a fall but rather lightning.

A masterpiece in Golden Gate Park by virtue of the artist’s debt.

Forgotten and then destroyed by fire, this was once one of the largest saltwater swimming pools in the world.

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

Historic house-museum dedicated to the revolutionary gay graphic artist Tom of Finland.

The giant pair of sexy legs sticking out the window of this costume store have become its main draw.

A man-made island in scenic San Francisco Bay.

A collection of memorabilia from the Beat era in the back of a San Francisco bookstore.

Join the circus for a few lessons to learn clowning, acrobatics, and Chinese contortion.

Barely visible foundations remain where Stow Lake’s “observatory” once welcomed visitors.

Decommissioned experimental solar facilities that pioneered solar energy technology.

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

The beautiful 1920 Pantages Theatre remains hidden just underneath the LA Downtown Jewelry Exchange.

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

Her final resting place was intended to be modest and private, but the power of her popularity continues to draw visitors.