Arizona's concrete crosses: Relics of Cold War history

Dotted throughout the desert south of the Valley lie relics of Arizona’s Cold War history.
 
In a 16-square mile grid near Casa Grande, giant concrete X’s make the desolate area look like a treasure map, but these crosses were instrumental in piercing the 'Iron Curtain.'
 
Arizona historian, Marshall Shore, said these cryptic 60-foot-wide crosses were part of the CIA’s Project CORONA. A mission that launched 144 spy satellites with high-powered cameras to photograph the Soviet Union and the Peoples Republic of China.
 
“As camera technology improved they realized they needed a way to focus the camera because they were just taking blind shots,” said Shore.
 
Hence the concrete crosses, known as calibration targets. The Arizona desert, with its clear and dry air, made the perfect location for the cameras to zero in and focus.
 
“It was said that there were over 250 of them and they were to be placed a mile apart and not more than a pencil lead difference from that mile to mile,” said Shore.
 
The crosses were poured by the US Army Map Service on leased land, most of them in place by 1967. It wasn’t until the project was declassified in the 1990’s that people found out exactly what they were used for, leaving behind decades of speculation.
 
“I've heard a lot of people thought they were sort of religious ceremonies because they're just large crosses in the middle of the desert,” said Shore.
 
So, if you stumble across one of these crosses in the desert, don't worry, it's not a bomb target, but it was key in keeping the US safe during the Cold War.
 
"They played a huge role in knowing what was going on,” said Shore. “The Russians could be saying we're going to attack but we could look at the film and see nothing is there.”
 
Project CORONA ended in 1972, and the crosses were no longer needed. It was the first time we ever recovered an object from orbit and produced stereoscopic space imagery.
 
If you want to check out one of the crosses for yourself, a couple of the more easily accessible ones are located just off Interstate 8, west of Casa Grande. One is located on the southeast corner of South Montgomery Road and West Cornman Road and another on the northeast corner of Trekell Road and Arica Road.