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

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

A mysterious monument meant to be a guide into "an Age of Reason" was destroyed after an apparent bombing.

The hide of Stonewall Jackson's equine sidekick is on display not far from where the ashes of his bones are buried.

This 29-ton granite ball spins around at the slightest touch thanks to a scientific phenomenon.

The resting place of a Civil War celebrity's amputated limb.

Outsider art meets paleontology at this roadside reptile repository.

A sacred site for Native Americans surveyed by George Washington and owned by both King George III and Thomas Jefferson.

This historic mansion was built as a symbol of love between a husband and wife.

The only recreation of William Shakespeare's indoor playhouse.

One of the last active volcanoes on the Eastern seaboard.

An organ located deep within a cave, whose "pipes" are the geological features of the cave itself.

Every equinox this Maya pyramid puts on a spooky ancient light show.

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.

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

Wondrous sandstone hoodoos where Native Americans collected clay for pottery, 9,000 years ago.

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

The largest earthwork effigy in the world.

Marking the spot where a conquistador gave up his search for the fabled Seven Cities of Gold.