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

The oldest still-existing mosque in the United States sits in a remote prairie in North Dakota.

These experimental weapons brought World War II to Nebraska as well as 26 other U.S. states.

The abandoned remnants of a little sanctuary for world peace that fell into disrepair.

A house turned museum is the real-life "home" of the fictional main character of The Wizard of Oz.

Their motto is, "We've been bonkers for hats even longer than you have!"

A piece of John the Baptist in the American heartland.

An abandoned cemetery lies in ruins as the surrounding forest swallows it whole.

America's first serial killer rests in anonymity.

This weeping, 10-foot-tall sculpture was a maquette for a 9/11 memorial.

Descendants of this colonial Pennsylvania family still travel from far and wide to visit the 300-year-old home of their Quaker ancestors.

Instruments, apparatus, and rare books all relating to chemistry and its related sciences.

A tour de force of a fountain, memorializing a man who loved fountains more than anything else.

Just a few miles from downtown Atlanta is a trail covered in a crazy collection of outsider art.

A house filled to the brim with oddities and curiosities.

The first park built over a freeway is a brutalist masterwork.

The tale of a strong-willed woman who stood her ground when the commercial world came rumbling in.

A huge musical sculpture and other art installations on the National Oceanic and Atmospheric Administration grounds.