The lowest point in the state of Illinois, at the confluence of the Mississippi and Ohio rivers.

Once one of the world's great cities, Cahokia was a place of religious worship, trade and mass human sacrifice before being mysteriously abandoned.

An acoustic anomaly with a mysterious cause.

World's smallest skyscraper, the product of a remarkable con.

This former Texas landfill is flush with 300 million-year-old fossils, all fit for the taking.

An enormous pink granite batholith, long attributed with spiritual powers by the Tonkawa Indians.

Once called the Jersey Lilly, this former saloon was the domain of infamous Judge Roy Bean.

Ghost town with a beer-drinking goat for mayor.

The scene of one of the darkest moments in American labor history has been left essentially untouched since the tragedy.

One of the Eight Wonders of Kansas and the first official National Natural Monument these stark formations look like nature's Stonehenge.

A whimsical monument marks the highest point in Kansas, not that you could tell by the looks of it.

Also known as the Cathedral of the Plains, this church holds the distinction of being one of the "8 Wonders of Kansas."

Despite its name, this route in southern Utah offers a heavenly day trip.

The cliff and rock formations are made out of Sioux Quartzite.

An eclectic assortment of medieval architecture in a small Iowa town.

Home with Gothic windows featured in a famous painting.

The longest of the four remaining covered bridges in Missouri.

This giant green head remembers one of America's jazz giants.

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

Even in death, he's still your huckleberry.

For over a century, it has been a tradition to raise a flag at the top of this 450-foot sandstone pillar on the 4th of July.

Two creeks flow out of either end of this canyon in opposite directions.

The hallowed remains of a 900-year old Ancestral Pueblo great house.

One of the American Southwest's most extensive collections of Navajo rock art.