Kriegsmarine -- U-boot?
Battle of Stalingrad -- [Battle of Kursk]? -- [Leningrad Siege]?
[Vichy France]?
Guernica -- Spanish Civil War -- Franco?
D-Day? -- [Invasion of Normandy]? -- [Operation Market Garden]? -- [Battle of Arnheim]?
[Battle of El Alamein]?
Gualdacanal? -- [Battle of Midway]? -- [Island hopping]?