Fort Monroe, decommissioned in 2011, provided coastal defense to the Chesapeake Bay and served as an artillery school for the Army from the early 1800s through the end of World War II. During that time, the Army fired unknown numbers of cannonballs, Parrott rounds and other ammunition from the fort and built mines for use in the harbor. Discarded military munitions, including explosives and potentially dangerous artillery components, likely remain throughout the site and adjacent offshore areas.