Eight rare Corvettes are swallowed up by a sinkhole in Kentucky's National Corvette Museum.

The city of Rockford, Illinois is symbolically protected by a quartet of fittingly stony sentinels.

This elaborate towering structure was once famed for its revolutionary height.

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

A place to eat for on-the-run agents and espionage enthusiasts.

An off-the-beaten-path place to literally hang beneath Milwaukee's Holton Street Bridge.

The show pony of cave systems, Fantastic Caverns manages to live up to its name.

The spot in the Mile-High City that's exactly 5,280 feet above sea level (at least for now).

Erosion and time have created a naturally-formed water park.

Just a man taking his prehistoric pet for a stroll.

Yo, Adrian!

The twin towers in this Chicago fountain use 50 foot tall video screens to spit on people.

Curious cave that stays a cool 56 degrees all year long.

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

The American Revolution was galvanized into serious action due to the tragic clash with British soldiers that occurred at this location.

The Denver airport is guarded by a 32-foot-tall sculpture of a demonic horse.

The sweetest graveyard in the world is filled with headstones for dearly de-pinted ice cream flavors.

This cave holds a surprisingly colorful variety of geological oddities.

One of the steepest streets in the United States makes an intriguing challenge for cyclists.

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

European castle ruins in an American state park are actually the product of death and grief.

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

The first declared National Monument in the United States.

The only structure left with direct ties to the Salem witchcraft trials of 1692.