D-Day

For those who don't remember, it was 70 years ago today.  A crucial battle in WWII.  The Anglo Americans loaded a huge army onto landing craft, motored across the English channel, and seized a defended beachhead and held it against Nazi counter attack.  This victory doubled the Nazi military problem.  It placed the Anglo American army on Germany's west side while the Red army was pounding on the east side. 
  D-Day could have failed.  Had the weather worsened, had the Germans deployed their forces better, had a number of other things gone wrong, the invasion force might have been thrown back into the sea.  Eisenhower was sufficiently worried to pen a press release accepting full responsibility in the event of defeat.  He never released it, but it shows he, the supreme commander with the best grasp of the situation, had his doubts. 
  If D-day had failed, it would have been a year or more before the losses could have been made good and the invasion tried again.  If  the delay had run on past August 1945, we would have nuked Berlin instead of Hiroshima.  Or the Russians would have cracked open the eastern front and invaded Germany pretty much single handed.  By this time in the war, Russian industry was up to speed and turning out weapons as good as the German's and in vastly larger quantities.  The Russians had a much larger and highly dedicated population to furnish soldiers to the front.  Had this happened, the cold war Iron Curtain would have started in Holland, instead of Eastern Germany.