How about famous battle locations? Could be done for multiple maps... i.e. Europe (Austerlitz, Waterloo, Leuthen, Rossbach, Mohacs, Lepanto, Tours, Crecy, Agincourt, Somme, Stalingrad, Normandy... time period wouldn't have to be a factor, and Europe has seen LOTS of battles over the past 2000 years...). Or, if you wanted to be specific in place and time, you could do the American Civil War (Vicksburg, Antietam, Gettysburg, Cold Harbor, Chickamauga, Pea Ridge, etc.). Just a few random ideas I had.