A monument to the forgotten French explorers and their landmark expedition.

The deserted railroad town had a last gasp as a ghost town attraction before being abandoned for good.

This old army installation has worn many hats throughout its history.

Grab a latte at the birthplace of modern American skateboarding.

Thanks to a loophole in property ownership, this alleyway has become a cacophonous street gallery.

A six-ton, 12-foot-tall concrete prairie dog is touted as the largest in the world.

Irontown was founded in 1868, as a second attempt to mine iron from the nearby Iron Mountain.

An abandoned World War II bunker is part of a chain that runs throughout Washington.

Built by an accountant with a dream of running a grand resort, this estate has sat vacant for over half a century.

After a catastrophic forest fire, a Greek artist transformed scorched tree trunks outside an old sanatorium into this haunting sculpture garden.

A chimney and a plaque are all that remains of a logging camp that once cleared out a large swath of Minnesota's old-growth forest.

Try not to get slimed in Tribeca.

The first fresco Diego Rivera painted in the United States can be found in the former San Francisco Stock Exchange.

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

A man-made island in scenic San Francisco Bay.

The grand, column-fronted, sculpture-adorned home of the ambitious digital library.

The remains of a 12th-century chapter house in Golden Gate Park.

This print shop boasts one of the largest pinball arcades in San Francisco.

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

The stones that traveled from Spain to eventually become a holy place for San Francisco's nature worshippers.

This turn of the century masterpiece has a mysterious goaty interloper.

A 300-ship graveyard, with a few still visible at low tide.

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

An 1870s ranch for pioneers, rodeo stars, and divorcees was abandoned and left for dead, until the city reopened it for exploration.