It's 1953. A mom and her son watch the mushroom cloud after an atomic test. But where was the photo taken?
The clue is the date. This rules out the Australia answer, because the Maralinga site was not decided until two years later. In 1953 the US conducted a series of eleven nuclear test shots (Operation Upshot–Knothole) at the Nevada Test Site. The test series was notable as containing the first time an atomic artillery shell was fired and for testing out some of the thermonuclear components that were later used for the subsequent massive thermonuclear series of Operation Castle (conducted on Bikini Atoll). Given the size of the explosions in the test, the one being viewed by the mother and her child is not at a very great distance, which rules out New Mexico and Arizona as possible locations.