English: The Corona Satellite Calibration Targets were built in the 1960s in the desolate Arizona desert. They are large concrete crosses in the ground with a resemblance of a large Maltese Cross. The targets are only visible if one walked up to them or passed over them from a great height, like space. The crosses were roughly arranged into a 16 x 16 grid so that the satellites could orient themselves and focus correctly before actually spying on America's Cold War interests. When the Corona project ended in 1972, a number of the crosses were demolished. Only a few still remain scattered throughout the desert. This one is located in Casa Grande on the southeast corner of South Montgomery and West Cornman Roads.
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