America's most famous piece of self-built architecture.

A theme park that suffered massive flooding during Katrina was abandoned, and now proves irresistible to trespassing explorers.

One man has carved a number of natural New Mexico caves into psychedelic sandstone temples.

This Boston medical museum features the skull of the famous medical case of Phineas Gage.

These old stone ruins in the Oregon wilderness were once bathrooms and are steeped in legends of murder.

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

Dramatic river bend surrounds a natural red-rocked pedestal.

A collision of human error and natural geothermal pressure created this rainbow-colored geologic wonder.

On the Oregon coast there is a natural hole that seems to be draining the sea.

Most-visited and most-photographed slot canyon in the American Southwest.

Bring your own cardboard to the slippery slopes of concrete hidden in a neighborhood park.

Rippling sand dunes frozen in the Arizona rock.

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

Old submarine parts have been converted into faux whale fins.

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

Make your reservation to have coffee with some kitties.

An old vending machine serves up unpredictable beverages from its seemingly magical insides.

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

A mysterious light of unknown origin on the backroads of Missouri.

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

A geological oddity formed by two rivers carving out a mass of limestone on both sides.

A college in rural Kansas founded to prepare the country for an impending World War III.

Cannon designed to fire an atomic warhead.

This historic cliffside mansion uses a natural cave for air conditioning.