Astronauts in the Grand Canyon: how Nasa used the west as a moonscape

Rare photos capture astronauts in the Apollo program training in the rugged canyons, craters and lava fields of Arizona

On 20 July 1969, the world paused as an estimated 600 million people watched Neil Armstrong and Buzz Aldrin walk on the moon. But few knew they were watching steps those men had long practiced in the canyons, craters and lava fields of Arizona.

Fifty years after the moon landing, Arizona's role remains a forgotten piece of history - but this pockmarked landscape of high rocky plains once served as Nasa's training ground for astronauts headed to the lunar surface.