All of the surfaces and angles of a Civil War-era fortress had names and this diagram will help you figure them out. Including the “banquette tread” (C) upon which the defenders of Fort Sanders’s key Northwest bastion sat (or slept) the night before the battle. Note the infamous “berm” (G) whose removal by the defenders played an important role in thwarting the attackers. Not to mention the water poured down the exterior slope (F) and scarp (H) which froze overnight to create a fatally-slippery surface.