A bastion's a structure projecting outward from the main enclosure of a fortification, situated in both corners of a straight wall (termed curtain), facilitating active defense against assaulting troops. It allows the defenders of the fort to cover adjacent bastions and curtains with defensive fire. The bastion was designed to offer a full range on which to attack oncoming troops. Previous fortifications were of little use within a certain range. The bastion solved this problem. By using a cann… (More on Bastions)