I can't think of a single, successful major amphibious attack that the Germans made during the whole war. The took North Africa from Libya, which was an Italian colony. Norway was very close to Germany and a very small country with an ineffective military and government. Still, it took awhile for the Germans to subdue Norway.
I'm sure the Germans realized they did not possess the necessary naval and marine capabilities to successfully invade Britain.
They thought they did. But Dunkirk proved that they really had no concept of using the sea militarily: they halted their advance and let the Expeditionary Force reorganize because they thought being against the sea meant the British (and friends) were trapped.
They had a similar strategic blind spot as far as air power. The whole organization of the Luftwaffe was built around air support for ground attacks. So the entire Battle of Britain was a matter of an air force that knew what it was doing -- the RAF -- against a numerically superior force that was fighting the wrong battle.
If the Germans had been organized with the goal of hitting Britain, with smashing France only a thing done on the way to hitting Britain, they could have swept across the Channel. I used to do military wargaming, and if the guy commanding the Nazis made capturing Britain THE goal, it was successful more often than not (if the commander just ignored the forces at Dunkirk and went ahead with launching an invasion, success was almost always achieved).
Interestingly, though, the Germans still tended to fail where both the Romans and the Normans did: at least the Scottish highlands, and always Ireland, remained free. So without some fair good fortune, a German invasion which swept over England merely shifted the Battle of Britain to be the Battle of Scotland and/or of Ireland. And once the Americans enter the war, they merely use Scotland and Ireland as the focus to take back England [although once, commanding the Americans, I successfully invaded southern France first, making the Germans divide their forces, thus making the task of taking back England easier).
Personally I think the crucial hinge of the matter was Churchill: with him as Prime Minister, there wouldn't have been a surrender even if England did fall; he'd have had the whole government off to Ireland and managed to make the Germans bleed themselves to death trying to take the Highlands.
I also think that if the Germans had succeeded in taking England, the U.S. would have been in the war right then. In a Churchill biography I read, thinking that Britain couldn't actually be invaded was a big element in why the U.S. didn't do more than send weapons; so if that had been shattered, I think it likely that Roosevelt would have been able to convince Congress that a declaration of war was in order.
In long-view strategic terms, then, the only difference would have been the length of the war, because what the Germans needed wasn't a successful invasion, but a British surrender -- something that just wasn't going to happen.
Are you that serious? Or do you not read what I post? I'm not using selective history. I know that the Russians were invaded, but the Germans sealed their own fate of invading Russia just like Napoleon did. Nobody has ever invaded Russia successfully. Hitler screwed up on two fronts. The British were only invaded once by the Romans and never again, and the Russians have never been because of the conditions of their winters.
Russia was successfully invaded by the Tatar Mongols. The British Isles were invaded by both Norsemen and Normans.
The only person who could successfully invade Russia from the west would be the Queen of Narnia -- she
likes winter.
