A Bomb Sight allows bombardiers to accurately drop bombs on a target, accounting for various factors such as the speed of the aircraft, wind, and altitude. Prior to World War I, dropping bombs was done by trial-and-error. Towards the end of the war, devices such as the Course Setting Bomb Sight could take input from control dials and the plane's instruments, removing a great deal of guesswork. Later systems would also incorporate autopilot, allowing crews to attend to other tasks en route to the target.