An acoustic anomaly with a mysterious cause.

Curious rock formations in a tiny Kansas state park.

An old spiral fire escape dangles above a public courtyard in Midtown Oklahoma City.

A Texas cave network is home to some of the world's most spectacular-looking and bizarrely named mineral formations.

The 7,000-year-old calcium carbonate formation creates a magnificent natural bridge.

A saloon and inn that served the Wild West's most iconic figures—and is still haunted by some of them today.

The highest bridge in America was built for an almost unnervingly small amount of money.

Strange red rock formations that have been attributed to a higher power for hundreds of years.

The quirky gift from West Berlin for the 1968 World's Fair still stands in Hemisfair Park.

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

Two small markers remember the Alamo's feline protectors.

Legend has it the commander of the defenders drew a fateful line in the dirt with his sword just before the final battle.

The official atomic museum of the United States explores the explosive and productive history of a much maligned energy source.

The oldest continuously occupied public building in the United States.

This giant pocket watch is the third iteration of a local landmark that has been standing just off the Santa Fe Plaza for over 100 years.

A small side chapel in Santa Fe's basilica is home to the oldest statute of the Virgin Mary in North America.

Wedding chapel's mysterious spiral staircase said to be miraculously constructed.

This museum started as a collection of Manhattan Projects and continues to add exhibits as they are declassified.

A multi-storied adobe complex has been inhabited for more than a thousand years.

This volcano rises like a giant anthill from the plains below, with a road spiraling up to the rim.

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

What was once a summer home next to a waterfall has now become littered with graffiti and children in swimsuits.

Collection of skeletal systems from the "world's leading supplier of osteological specimens."

An immersive art experience built by local arts collaborative, Factory Obscura, in the building formerly known as The Womb, a psychedelic arts center founded by the frontman of the Flaming Lips.