ROYALTY FREE LICENSE - This is the Citadel at Fort Pike, a Third System fortress built to guard the Rigolets Pass, near New Orleans, Louisiana. Notice the rifle ports dotting the crumbling walls of the Citadel, which served both as a barracks and a last line of defense for Fort Pike. Were invaders to get over the walls, the fort's garrison could retreat to the Citadel and continue to fire upon the enemy through the rifle ports. Seen behind the Citadel is the sea-ward wall of Fort Pike, showing the arched entrances to cannon emplacements - casemates. Just at the left center edge of the image are seen the ruins of a hot-shot furnace, which was used to heat cannon balls to be fired onto wooden ships in hopes of setting them ablaze.