Fort Miles is the partly-restored Second World War coastal artillery installation inside Cape Henlopen State Park. Built starting in 1941, it housed sixteen-inch guns capable of reaching enemy ships nearly thirty miles out into the Atlantic. The site is now a museum: barracks, plotting rooms, a restored gun battery, and one of the original sixteen-inch guns (recovered from a battleship and moved to the site for display) sit among the pines just behind the dunes.
The museum is staffed by volunteers, many of them veterans, and is open weekend afternoons in summer and on a more limited schedule the rest of the year. The site is a few miles from the town centre — drive into the state park and follow the signs.