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, free for veterans and active service members, cost is $6 for all others. Register online, destateparks.com/Programs or by calling 302-644-5007.