This photo shows the crater made by the Sedan nuclear test, also known as the Storax Sedan test, which happened today in 1962 as part of Operation Storax. The crater is the result of an explosion that displaced twelve million tons of earth, and at 320 feet deep and 1280 feet in diameter is the largest man-made crater in the United States. It's also—bizarrely we think—listed on the National Register of Historic Places, especially weird when you consider that it sent two radioactive plumes wafting northeast from the Nevada explosion site, cross country from state to unsuspecting state, to settle especially heavily upon Iowa, Nebraska, South Dakota, and Illinois. Of all the nuclear tests conducted in the United States, Sedan ranked highest in overall activity of radionuclides in fallout, distributing nearly 7% of the total amount of radiation which fell on the U.S. population during all of the nuclear tests at the Nevada Test Site. Historic indeed. You see the explosion that caused all that below.