The demilune, meaning “half-moon,” protected the fort’s entrance. During the Civil War, its wall was about waist high, with gun platforms on the flat top. After the Civil War, while Fort Pulaski remained a military post, Army engineers constructed earthen mounds to hold powder magazines. The demilune as it appears today includes a large mound built in the 1890s to house the control center for mines placed in the North Channel.