Civilian casualties on D-Day and D+1
In 1944, by a huge coincidence, a crossword puzzle was printed with answers all containing D-Day operation "code names", which sent MI-5 into a panic thinking their invasion plans had been discovered.
In 1942, the Canadians and the British Navy launched a practice invasion of France, the "Dieppe Raid." 20% were killed, 10% wounded, 30% captured. The lessons learned in that disaster lead to D-Day's success.
Theodore Roosevelt Jr was the only General involved in the initial assault on D-Day, after insisting to his superiors to be one of the first ones off the boats. He survived, then died of a heart attack one month later.