A promotional sun clock on the site of San Francisco's great raceway.

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

The only theatre in the world constructed specifically for sound movement.

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

A 140-year-old castle with underground caves hidden in San Francisco.

A psychedelic labyrinth on the San Francisco bay.

Home to the story of the outlaw turned funhouse mummy, Elmer McCurdy.

This crumbling UFO is one of only a few remaining "moveable ski chalets" of its kind.

Tiny historical streetcars wind through a small scale version of Crescent City in this whimsical train garden.

The stone labyrinth in this New Orleans city park was laid to symbolize healing in the wake of Hurricane Katrina.

A 19th-century shrine covered with prosthetic body parts as votive offerings.

The crumbling ruins of this southern American fort have survived storms, war, and cults.

Pirates had to be ousted from the land where this now ruined Louisiana fortress was built.

This museum chronicles the history of a leprosy quarantine hospital that then became a refuge.

One of the longest water bridges in the world was built over a supposedly haunted swamp in Louisiana.

At the supposed instruction of Ben Franklin and Socrates, a Spiritualist believer intended to birth a mechanical messiah here.

Home to the infamous "Typhoid Mary" and the worst loss of life in New York's history prior to September 11, 2001.

A particularly creepy abandoned hospital that sparks interest for lovers of the supernatural.

A mysterious find dredged from Louisiana waters.

World's largest precision optical instrument used to detect Einstein's elusive gravity waves.

Roadside attraction with more than 1,000 stuffed and mounted animal skins displayed in simulated natural habitats with hand-painted backdrops.

An impressive collection of dollhouses and an homage to the frog-leg canning industry.

A 19th-century utopian religious society designed to align with the latitude of Jerusalem.

A haunting, yet lovingly hand-hewn potters' field full of graves that flood with each heavy rain.