Evil scientists used weapons that could change the weather, which led to the D-Day battles in Normandy failing in the storm. In 1945, the Nazis set off an experimental Antimatter Bomb, destroyed most countries in the world, and destroyed social rule. This day is called Zero Day, or Z-DAY for short.
https://play.google.com/store/apps/details?id=com.kingsgroup.ww2&hl=en_US

