Recovered from the brink of extinction, at home in the Financial District.

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

A man-made island in scenic San Francisco Bay.

An overlooked and unassuming engineering marvel.

The miraculous hydrant that saved the Mission District in 1906.

Since 1973, this block has been home to the most concentrated collection of murals in San Francisco.

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

Not merely a museum – but a whirring powerhouse that offers a subterranean peek into the heart and soul of cable car operations.

A hidden subterranean installation offers a view of the sky.

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

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.

San Francisco's urban bison herd has persisted in the face of extinction, development, and disease.

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

A shop full of natural curiosities, carnivorous plants, and costumed taxidermied mice.

A collection of 20th-century automata, penny arcade games, and musical contraptions.

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

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

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.

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

These light, hollow rolls have been linked to Acadia National Park since the 1890s.

Egyptian Revival obelisks still rise over the old mine shafts.

A comedy troupe's collection of bizarre humor.

The highest peak in the state of Vermont has some interesting features.