Rock-cut cave complex filled with ancient Buddhist artwork.

The second-longest continuous wall on the planet protects a hidden secret in the deserts of India.

Once an indicator of social class, the color blue has come to define this city on the edge of the Thar Desert.

The remains of what was, not so long ago, the world's largest city.

This complex of vertically-excavated Buddhist, Jain, and Hindu monolithic temples in India's Maharashtra providence illustrates a spirit of tolerance characteristic of ancient India.

These ruins of a pre-Columbian cliff village are among the most beautiful and well preserved in New Mexico.

More than 21,000 images fill this overlooked gem of a prehistoric site.

A museum dedicated to the alleged Roswell Incident.

Despite time, colonization, and the brutal New Mexican heat, these Pueblo ruins still stand.

This volcano rises like a giant anthill from the plains below, with a road spiraling up to the rim.

This towering volcanic plug stands out among the dramatic formations that dot this otherworldly desert valley.

The shattered remnants of a meteor that struck Santa Fe more than a billion years ago.

These Pre-Columbian petroglyphs contain representations of birds, deer, hunters, and even some early Native flute players.

A unique geological area spiked with wind-carved rocks that resemble teepees.

Natural sonic phenomenon comes with a grisly legend of murder and blood.

A preserve with 75,000 ancient drawings remains the realm of public – not just scientific – exploration.

65 million-year-old chalk outcroppings mark the end of the Jurassic Coast.