Radiolab Episode on Japanese Balloon Bombs

This is an excellent bit of radio about one of the weirder forms of attack during World War II---the only one I know of that produced casualties in the continental United States: balloon bombing. I had heard about this initiative before, but this report is, true to Radiolab standards, a really informative and interesting piece. In a nutshell, the Japanese during World War II were committed to figuring out how to bomb the US mainland, but lacking the forward air power to do so, they tried instead launching 9,000 hydrogen balloons (made by school girls) with bombs attached. US authorities kept the balloon bombs secret during the war even after a number of them went off---including one incident at a picnic at which several people were killed. After the war, a number of balloon bombs were recovered, but one showed up only very recently, and others have likely never been found. Along with the Nazi saboteur landings that led to Ex Parte Qirin, the balloon bombs are a largely forgotten part of Axis efforts to bring the war to America's shores---a part that did not lead to a Supreme Court opinion and that did not enjoy a post-September 11 revival.