The secret city built by the Manhattan Project.

The highest point in North Carolina and the United States east of the Mississippi River, Mount Mitchell is named after argumentative explorer Elisha Mitchell.

This WWII-era military installation once held an entire city within its walls - now, its walls are falling down.

Thousands of pieces of art have been carved into the rock at the site of an ancient volcanic eruption.

A wealth of pop culture statuary and green chile dishes give this roadside restaurant clout.

A one-of-a-kind sundial at the Very Large Array honors a radio astronomy pioneer, incorporating the original piers from his breakthrough radio telescope.

This quirky hot springs town known to locals as "T or C" was named after a radio show.

Once the product of an inexplicable gold strike, this ghost town is now home to one man and his love of classic machines.

A Wild West jailhouse that slid down the mountainside.

Ninety feet off the valley floor is an ancient dwelling put under protection of the U.S. government by Teddy Roosevelt.

This 24-acre park offers a place for meditation in the midst of Sedona's iconic red rocks.

The world's only teal arches exist in a city that cares more about its aesthetic than an Instagram influencer.

An ornate Art Deco tile mosaic representing Nebraskan life, both modern and prehistoric.

This mechanical wonder towers above a river in Michigan's capital city.

Perched atop a brick smokestack, this enormous lug nut symbolizes the local minor league baseball team.

HFH's slum simulation is either a noble recreation of poverty or a cringeworthy attempt at same.

The site of the notorious Camp Sumter Prison is now a peaceful memorial.

A statue honoring 44 continuous years of greeting passing ships.

"X" marks the spot of an echo chamber in the middle of a plaza.

Bronze footprints mark the path where a civil rights leader tried to march in peaceful protest before being knocked unconscious.

The walls of America's oldest masonry fort famously "swallowed" cannonballs.

In this case, 'zero' marks the spot where the iconic Old Spanish Trail ends.

An 18th-century Spanish watchtower made entirely of seashell and concrete.

Two men built this castle on the Florida coast as an artistic “landscape sculpture.”