This former coal gasification plant found a curious second life as a popular public park.

A former hospital is now home to a pizza parlor and maybe a few ghosts.

For nearly 50 years, this San Francisco nonprofit has been serving as a mix of recycling center and art school.

A tiny theater hidden in an alley plays a constant stream of short silent films for anyone willing to peer through the peephole.

This one-block alleyway is stuffed with street art that is colorful, cultural, and intensely political.

This massive redwood tree has stood in Northern California for nearly 2,000 years.

This massive redwood tree has a hole in the base big enough to drive through.

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

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

A beautiful geyser under environmental threat.

Nevada's largest cactus collection stands outside a candy mogul's small factory.

The peaceful space is adorned by paintings by the famed abstract artist Mark Rothko.

Home to the largest urban bat colony in North America, estimated at 1.5 million bats.

A gorgeous garden oasis with winding paths, stone bridges, and a troubling history.

This big empty pig is a nostalgic throwback to mid-20th-century Texas barbecue.

An ivy-covered arch bridge dedicated to Tejano music singer and legend Rosita Fernandez.

A 131-year-old wunderkammer of Texas history.

The marker offers a rare chance to be in four U.S. states at once, though there's some controversy over its geographic accuracy.

A small section of Boise, Idaho maintains the unique culture and traditions of the Basque people.

The largest outdoor art gallery in the Northwest United States.

The largest island on the great salt lake is home to curious creatures and strange stories.

A hidden garden of stones engraved with scriptures, a Joseph Smith Sphinx, all carved by one man.

Visitors to this library are in for a real-world education in modernist architecture.

If drivers cross the rumble strip on this stretch of Route 66 at just the right speed it plays "America the Beautiful."