Natural rock water slides hidden in the remote forests of northern Idaho.

Home to the deepest rift anywhere on Earth.

An unusual geological feature towers over the remains of a dark episode in United States history.

Around half a million years ago, these magnificent columnar basalt cliffs were formed from cooling lava.

This rustic old building is said to be the most photographed barn in America.

A miraculous natural phenomenon known as "the spring that breathes."

An architect's childhood fantasy treehouse made real.

The first declared National Monument in the United States.

Over 600 acres of idyllic open grassland honor Nebraska’s georgic storyteller.

This was the first homestead registered after President Abraham Lincoln signed the Homestead Act into law.

When an ancient supervolcano erupted, some of Nebraska's prehistoric animals were forever preserved in ash.

Site of the 1879 Cheyenne Outbreak and the site where famed Sioux chief Crazy Horse met his fate.

Other-worldly rock formations and ancient fossils abound in this unique stretch of Nebraska badlands.

This erect, phallic geological spire wasn't always named so domestically.

An experimental, automotive replica of Stonehenge.

Where experiments are conducted on all things wood.

Where condemned pirates met their grisly end at the gallows on the River Thames.

Home with Gothic windows featured in a famous painting.

The remains of a bustling turn-of-the-century park built to showcase the wonders of electricity.

A half-mile long and three stories high, this bridge over the Des Moines River Valley mimics a descent into a mine shaft.

This narrow canyon has been carved by the river over thousands of years into spectacular and curious forms.

Even Henry David Thoreau found this glacial pothole irresistible.

This picturesque abandoned home is rumored to be a spite house.

A stone memorial erected for New Hampshire's only convicted witch.