It’s a simple innovation that helped win a war. The Bailey bridge was Donald Bailey’s innovative solution to a number of wartime obstacles. The allies needed a way to cross bodies of water quickly, but bombed-out bridges — or an absence of crossings entirely — made that incredibly difficult. That was only compounded by new, heavy tanks that needed incredibly strong support. Bailey’s innovation — a modular, moveable panel bridge — solved those problems and gave the allies a huge advantage. The 570-pound steel panel could be lifted by just six men, and the supplies could fit inside small service trucks. Using those manageable materials, soldiers could build crossings sufficient for heavy tanks and other vehicles. As impressive, the Bailey bridge could be rolled across a gap from one side to the other, making it possible to build covertly or with little access to the other side. Together, all the Bailey bridge’s advantages changed bridge construction and may have helped win the war.