This nondescript tunnel has been featured in a number of iconic movies, from “Roger Rabbit” to “Back to the Future.”

The highest pedestrian bridge in Singapore looks like a series of undulating waves rising between two public parks.

On Waikīkī Beach, a monument to four extraordinary individuals of dual male and female spirits who brought the healing arts from Tahiti to Hawai'i.

Once thought to be the oldest living tree in the world, Methuselah was germinated before the Egyptian pyramids were built.

This fast-food outlet is the only space and UFO-themed McDonalds in the world.

An abandoned town is hidden in Great Smoky Mountains National Park.

One man’s religious convictions led him to build this stone castle meant to withstand an apocalypse.

One man has spent decades faithfully constructing this unique brick and cinderblock castle.

The "Fun Spot of the Desert" is now a haunting ruin, and a reminder that putting a water park in a desert is a bad idea.

Rusty pieces of metal jutting out of a breakwater are all that's visible of the 12,500-ton ocean liner that capsized just off the beach.

Abandoned in 2009, this once popular resort destination now stands frozen in time.

The disdain for this dysfunctional dam is reflected in a giant pair of scissors painted on the concrete face.

Inky sludge oozes to the surface of this beach thanks to a rare natural tar seep.

Happy harbor seals frolic and snooze on this warm, sandy stretch of coast.

At 130 years old and 126 feet tall, it is the largest known example of the rare Torrey pine tree.

The beautiful behemoth is one of the largest trees of its kind in the United States.

This house is a mosaic of tiled artwork sourced from local artists.

Acres of natural wonders left behind by a socialite-turned-gardener.

This nonsensical smiling boat shuttles passengers between two places they could've easily walked between.

This little gem of Spanish Colonial architecture has been abandoned since the 1950s.

The first attack on the continental U.S. during WWII occurred off the coast of a quiet California golf course.

The abandoned personal amusement park of the King of Pop.

Colorful Native American paintings are hidden within this small cavern.

Hidden in the Santa Ynez Mountains off Highway 154, this tiny restaurant once served as a stagecoach stop.