 Wallis foresaw that disrupting German industry would remove its ability to fight, and also understood that precision bombing was virtually impossible in the late 1930s.The technology for precision aiming was developed during World War II, and Barnes Wallis' ideas were then shown to be superbly successful (see for example the Bielefeld raid 14 March 1945), considering the standards at the time.Wallis' first concept was for a ten-ton bomb that would explode some underground.