Rippling sand dunes frozen in the Arizona rock.

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

The drama of nature in full effect in this Nevada State Park.

A fortified city, home to a remaining population of five families

One of the most spectacular canyons in the world.

Unique geological formations in China, featuring some suggestive shapes.

Unusual, mushroom-like rock formations caused by weathering and water erosion, set to disappear, according to geologists.

The tallest stationary dunes on Earth also happen to sing.

This "floating island" plateau sits 7,671 feet above the forest floor.

An Australian lake whose pink hue defies scientific explanation.

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

World's largest cave was only discovered in 1991, and now offers tours to the public.

Every autumn, this hillside is ablaze with red summer cypress.

A seemingly endless landscape of pure salt stretches far across Bolivia.

Breathtakingly blue walls shimmer inside the "Glacier Behind the Town."

The king of U.S. high points towers over every other peak on the continent.

On the Oregon coast there is a natural hole that seems to be draining the sea.

A fifth-century temple improbably built into the side of a cliff.

One of the world's largest ice festivals dazzles visitors for over a month with radiant sculptures and carvings.

A colossal floating restaurant built to look like a ancient Chinese imperial palace.

Remnants of the most densely packed city in world history, that thrived on anarchy for 30 years.

Teeming with illegal goods and services, this towering maze of vice is also a popular tourist accommodation.

A hard-to-reach oasis in a desolate corner of Death Valley National Park.

The rocks in this arid basin leave trails of movement behind them.