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

An apocalyptic seismic event creates a deadly chain reaction that ends with a 6-mile long lake developing within weeks.

An entire town preserved as a historic landmark.

A smoke stack so large, the Washington Monument could fit inside!

New fungal and bacterial species call this deadly lake home.

Twenty-seven massive radio antennas on the high plains of New Mexico search for life on other planets.

This immigrant bridge once spanned the Thames but is now a fixture of an Arizona city.

The highest point in Arizona is an oddly snow-topped peak within the otherwise arid state.

See massive fossils that are over 200 million years old in northeastern Arizona.

This Arizona observatory is famous for investigations into Martian life, and as the place humans first spotted Pluto.

Ancient pueblos built into the base of a natural canyon wall.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

A small metropolis of Pueblo cave dwellings have been carved right into the hillside of this national monument.

The highest bridge in America was built for an almost unnervingly small amount of money.

When ecosystems collide in the arid Southwest.

A phenomenal assembly of pueblos in New Mexico is the most complete example of ancient ruins north of the border.

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

An Aztec temple, the largest man-made pyramid in the world, sits buried in earth with a Spanish church set on top.

A massive yet whimsical statue pays homage to the art and joy of "flight."

A hidden treasure of an abandoned city lies deep in the jungles of Campeche, Mexico.

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

A massive underwater sinkhole made famous by Jacques Cousteau.

An elaborate Mayan city shrouded in alien conspiracy revealed the tomb of Pacal the Great.

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