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

Once the fastest ship from San Francisco to Tahiti, the Galilee now lays in pieces in three different cities.

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

The only visible piece of San Francisco's most famous shipwreck.

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

A hidden gem, named after a San Franciscan icon, offers spectacular views of the Pacific Ocean.

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

Big gun installations, built over a massive cemetery, now abandoned & hidden in trees.

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

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

A library built during San Francisco's pioneer times is a student's retreat, bibliophile's sanctuary, and chess player's delight.

A quiet nook at the top of a little-known hilltop park named after California's first poet laureate.

This bakery sits on the site of the Black Panther Party's first headquarters.

With statues of Nelson Mandela and Harvey Milk this monument has been called the Mount Rushmore of California.

With the touch of a button, you can read a randomly selected short story.

Staircase winds down the side of Telegraph Hill through gardens, wild parrots flying overhead.

These six walrus head statues harken back to a time when this area wasn't far from the oceanfront.

Shoot for par over the bodies of the dead on this cemetery-cum-golf course.

The United States' first transcontinental automobile road came to its end at this spot in San Francisco's Lincoln Park.

The oldest house in the capital of Silicon Valley.

At the base of the Golden Gate Bridge, a small sign basically begs for a high-five.

Beneath the southern end of the Golden Gate Bridge is the “Gibraltar of the West Coast,” a fort built to protect the San Francisco Bay from naval attack.

Inside an old airplane hangar, friends and strangers alike play on a massive trampoline.

A monument to the love people have for their pets.