The enormous 250-room Vanderbilt mansion conceals hidden doors and secret passageways.

A historic dam made famous for its turbines and feature in a Hollywood classic.

One street divides a single town that stands in two U.S. states.

This once-booming Gold Rush town is now home to a herd of feral donkeys.

This public square capitalized on a single Eagles reference to bring some life back to an Arizona town.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

This Arizona observatory is famous for investigations into Martian life, and as the place humans first spotted Pluto.

A planet-hunting astrograph built in the 1920s to seek out the so-called "Planet X" beyond Uranus.

Explore the largest pure gypsum deposit in the world, and go dune sledding while you're at it.

A museum devoted entirely to the rattlesnakes and snake-related art.

The old Route 66 town straddling Texas and New Mexico died along with the Main Street of America.

Once in disrepair, this popular Texas stop along iconic Route 66 has been restored to its past glory.

A sculpture made of 10 Cadillacs as a monument to the "Golden Age" of the American automobile.

This water tower slanted at an uncomfortable angle off the old Route 66 was an ingenious marketing ploy.

A local landmark with generations of spraypainted messages, and more being added each day.

This now-deactivated naval base defended the Florida coast for centuries.

Pensacola's UFO home has withstood many hurricanes—just as the experimental 1960s design intended.

A giant toy jack made of numerous welded-together fire hydrants.

This 38-drawer structure claims the superlative title, but it isn't the world's only giant filing cabinet.

The first declared National Monument in the United States.

Outsider art meets paleontology at this roadside reptile repository.

This historic hotel on Bathhouse Row in Hot Springs National Park has a storied history of gangsters and baseball greats.

Town not known for anything except its strange name.

A beautiful South Korean gate and garden in Little Rock honors American Taekwondo.