#DYK: the Fort Benning trench system was built in 1920 to train #Infantry officers in the tactics of trench warfare. Fort Benning phased out WWI style trench training in the late 1920s and lessened use of the trenches over the next decade. As they fell out of use, trees and erosion rounded their once-sharp crenulated edges and they became impossible to recognize from the ground. They remained forgotten and mostly undisturbed until Fort Benning archaeologists accidentally discovered them by obser