The weather cleared just enough for the planes and gliders to make the trip, so the ships set sail. Hundreds of them. The 101st Airborne was supposed to drop far behind the beaches, operating as an advance force to keep the Germans from reinforcing. Apparently the Allies forgot about the German anti-aircraft guns, which forced many of their troop planes to veer way off course, the paratroopers jumping wherever they could. The gliders, which were supposed to carry commandos and supplies were also a bust.
When the troops arrived at Normandy, they managed, for the most part, to catch the Germans flat-footed. Not unprepared, not willing to defend, just stunned at the sheer mass of troops and supplies suddenly coming ashore. Of course, the Americans got off relatively easy; British landings were far more hotly contested, which not only slowed down the entire operation - retaking France - but induced in Field Marshall Montgomery a caution that hampered relations between the British and the Americans (it didn't help that Patton was quite vocal in his disdain for Monty).
Famously, the American beaches included some cliffs, and Army Rangers had trained to climb those cliffs. To this day, I have no idea if anyone told those Rangers the Germans had fortified right up to the lip, and were more than willing to rain fire down as they tried to climb. That the Rangers not only managed to make it to the top, but take and hold those cliffs is a wonder.
Eisenhower, Supreme Allied Commander of the European Theater of Operations, had written two statements for press release. Fortunately for us all, the one praising the heroism of the troops yet accepting responsibility for the dismal failure of the landing was never released. We tend to think of the landing, the march across northern France, and the collapse, less than a year later, as inevitable. Yet, nothing is inevitable. The Russians, bled white in their war with the Nazis were pushing hard on the eastern Front, yet the Germans still had enough manpower to stop the Allies cold for a while.
While the numbers of those still alive who participated in the D-Day landings dwindles ever faster, there are still a few left. If you know one, or know of one, thank them, because our world is a much better place because of them. My oldest sister's father-in-law is one such; while he was gravely injured - he was near the front of his Higgins Boat and took both machine gun and grenade fire - he nevertheless helped us save Europe, and perhaps the whole world from the destructive passions of the Nazis.