I'm currently watching Troy and as much as it is based on mythology, it has got me wondering. With all the thousands of arrows and spears thrown, how come archaeologists don't find these thousands of arrows and other weapons littering the ground? I know about how wood and other decomposing materials wouldn't last thousands of years and shifting/layering of the ground (which I don't fully understand either) can alter the level of which the actual battle was fought on, but how come more of these objects aren't found on a massive scale?