The white cross, located in Casa Grande, Ariz., was created in the 1960s and used by the United States military to calibrate its Corona spy satellites.
Spy Satellite Calibration Target
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Anonymous
@ 2011-11-19 07:15:24
There are many of these in the area. I've found over 100 of them with Google Earth. There used to be over 200 of them in a 12 mi x 16 mi grid, spaced every mile. Many, especially in Casa Grande and Arizona City, have been removed over the years as housing tracts, roads, and other construction has occurred.