A waterfall 600 ft. inside a mountain, once the bane of gold miners, is now a spectacle of nature.

One of the largest private collections of fossils in the world.

A fitting attraction for the corn capital of the world.

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

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

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

The oldest experimental corn field in America is still creating better ways to grow crops.

This Mediterranean castle was built for a millionaire and his giant dog.

A roadside statue store in rural Minnesota with quirky displays.

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

After the musical legend's death, his memorial was mysteriously graffitied in gold.

The home where a lovestruck Fitzgerald wrote his first published novel, "This Side of Paradise."

Equal parts record-breaking temple to consumerism and bizarre fun park, it's more than you think it is...

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

Home to the Amorphophallus titanum "Corpse Flower," which is among the largest flowers in the world and also smells powerfully of rotting flesh when in bloom.

A toweringly silly piece of modern art has been delighting locals since the 1980s.

A unique work of outsider art sourced from scrap metals and signifies conservation.

At a mile long, the Fort Madison Bridge is the largest double-decker swing-span bridge in the world.

This hand-carved wooden carousel in the Story City North Park was built in 1913.

The oldest university museum west of the Mississippi retains its 19th century feel.

A small burial plot formerly stranded in the middle of a road.

The magazine keeps a perfectly groomed display garden for its photo shoots.

An Iowa town celebrates its heritage with the tallest working Dutch windmill in North America.

Millions of dollars worth of sculpture decorate this Iowa city center.