One of nature's most well-scheduled phenomenons resides in Wyoming's Yellowstone National Park.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

One of the smallest towns in the United States.

Paranormal experiences in this hotel's room 217 led Stephen King to write "The Shining."

This "zoo" is a cross between a junkyard and a sculpture garden, featuring animals you won't see anywhere else.

The remains of the dam that unleashed a 15-foot wall of water on Denver.

A geological mystery on Camelback Mountain.

Giant, natural amphitheaters made of delicate geological formations called "hoodoos."

This rugged area of red rocks and arches is often considered one of the most beautiful places on Earth.

A sharp bend in a dramatic river canyon cut through red rocks.

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

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

Aqueducts have dramatically changed this old lake, now home to tufa towers and its very own species of tiny brine shrimp.

A vast city of the dead, where the deceased outnumber the living by more than a million.

The oldest burial ground in the city, final resting place of city founders, Ohlone natives and murderers alike.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

No telescopes, no power, no gift shop: The Observatory of Chichen Itza, one of the world's oldest observatories, takes astronomy back to basics.

Send a postcard while vacationing with Satan.

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

A massive underwater sinkhole made famous by Jacques Cousteau.

This neon blue river gets its color from a unique mix of bacteria and volcano minerals.

Death rituals and sacrifice inside a Peruvian megalith.

The stones of this Incan wall complex fit together so well you couldn't fit a piece of paper between some of them.

The intricate stonework of Machu Picchu serves as a testament to Incan engineers.