Battery 519 tour, 11 a.m., Cape Henlopen State Park, Fort Miles Museum, Lewes. Construction began in 1941 under threat of war. Discover what threats there were and how Fort Miles planned to defend U.S. from them. Recommended for ages 7 & up, cost is $6, free for veterans and active service members. Register at destateparks.com/Programs or call 302-644-5007.