D-Day Could Easily Have Been An Epic DisasterAndrew Liptak6/06/15 6:15pm21125EditPromoteDismissUndismissHideGo to permalink71 years ago today, Allied forces stormed the beaches of Normandy. Operation Overlord was the largest amphibious invasion to date, and created a foothold in Europe. The key to winning? Careful planning and training. And while the invasion was a success, it was a risky gamble that could have gone disastrously wrong.