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

The world's largest mountain carving could fit all of Mount Rushmore inside it many times over.

This prehistoric sinkhole lured exclusively male mammoths to their death, much to the delight of science.

America's largest man-made forest was planted in an effort to bring back the past.

This replica stave church looks like a piece of Norway was simply plopped down in South Dakota.

Every president in history is immortalized in bronze in downtown Rapid City.

Thanks to a loophole in property ownership, this alleyway has become a cacophonous street gallery.

One of America’s oldest and spookiest hotels, thanks to the residency of ghosts, dead presidents, and Alfred Hitchcock.

A six-ton, 12-foot-tall concrete prairie dog is touted as the largest in the world.

The granddaddy of all tourist traps, built on ice water, jackalopes, and a giant dinosaur.

A fitting attraction for the corn capital of the world.

Just a man taking his prehistoric pet for a stroll.

The deserted railroad town had a last gasp as a ghost town attraction before being abandoned for good.

A striking sculpture built to honor the women of the Lakota and Dakota Nations.

A rancher expanding a natural spring for his cattle came up with bones – lots and lots of them.

Otherworldly rock formations and ancient fossils abound in this unique stretch of Nebraska badlands.

This large midwestern cavern features impressive rock formations and an underground waterfall.

The statue of John Harvard isn't actually John Harvard—or even, technically, the founder of the school.

Believe it or not, the now-ubiquitous California avocado originated in Guatemala.

This old residential building was once the largest flour mill in the world.

One of the world's premier laboratories for hydraulic engineering research takes full advantage of the water's power.

The only arched bridge made of stone on the entire Mississippi River.

When flour explodes, it's not a pretty sight.

Fresh wooden posts have been added to ancient holes to recreate a primitive henge clock.