An extraordinary "City of Caves" carved from solid stone.

Oregon's unexpected high desert, displaying layers of time in a colorful show.

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

An elaborate shrine dedicated to the four corners of the world unfortunately misses its mark.

The enigmatic and seldom visited ruins of a Mayan city-state.

A monument celebrating the idea of reaching inaccessible places.

A historic presidential getaway on the continental United States' southernmost island.

The former home of the Nobel Prize-winning American writer is now home to dozens of six-toed cats.

These remote Florida islands have a history of sea turtles and sunken treasures, and one of the world's largest coastal brick fortresses.

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

This sculpture by artist Fritz Keonig survived the 9/11 attacks and now stands as a monument to the victims.

This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

Elevated freight railway turned wildly successful urban park.

The only castle in North America to ever house European sovereigns.

Dramatic river bend surrounds a natural red-rocked pedestal.

A spiritual vortex among the red rocks in Sedona.

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

After starting as a whimsical tourist attraction that eventually found its way to ruin, these renovated canals offer a lush and exotic locale on the Pacific Coast.

A three-story, three-dimensional hobo clown in a tutu welcomes CVS shoppers.

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

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

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

An abandoned Jazz Age dream home and con man's hideout in Death Valley.

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