The remains of a ruined mansion memorialize the 1906 earthquake.

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

San Francisco's newly reopened hands-on science museum.

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

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

Relics of the 1894 Midwinter Exposition continue to delight visitors today.

Carnivorous plants, medieval aphrodisiacs, and the largest original wood structure glass conservatory in the western hemisphere.

Get lost in this haunting fairytale art walk through a man-made eucalyptus grove.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

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

Bring your own cardboard to the slippery slopes of concrete hidden in a neighborhood park.

An artsy hidden staircase leads to breathtaking views of San Francisco.

A huge musical instrument played by the ocean.

This former rail stop in Utah was abandoned, repopulated by some nostalgic friends, and now is home to a single DIY aviator who lives in a hangar.

A sculpture for the sun and stars, created by Nancy Holt.

Over 315,000 preserved amphibians and reptiles in jars.

One time home to turn of the century explosives, now hidden under the Bay Bridge.

340 bicycles, 65 feet high.

The haunting ruins of Jack London's dream house.