The Allies dropped over ten million bombs and rockets on European targets during World War II. Most were used on Germany and Austria. Not all of these bombs exploded. No one is sure how many buried themselves into the ground without detonating, but each year, fifty of them are encountered in Austria alone. Normally, these rather ancient bombs are defused (the fuse carefully removed from the front of the bomb, and the bomb itself then carefully carried away to be safely detonated in a remote area). But some of these bombs used a chemical fuse, and the decades in the ground have made the chemical fuses very unstable. On July 17th, two Austrian bomb disposal experts were killed, and a third severely injured, when a 250 pound bomb exploded while they were trying to remove the chemical fuse. That was the worst accident suffered by the Austrian bomb disposal service since 1946, when they began to clear away the unexploded bombs. In addition to the thousands of unexploded bombs thought to still be in Austria, there are perhaps as many unexploded artillery shells and rockets. In addition to that, there are also hand grenades, landmines and other munitions buried in areas that saw heavy fighting. Construction workers are trained to dig carefully in such areas, and will probably have to do so for several generations, or longer. French and Belgian farmers continue to unearth World War I era munitions, and every once in a while, American farmers or construction workers encounter munitions from the American Civil War.