How could things have turned out if The UK had decided not to guarantee Polish independence and not intervened in the German invasion of Europe? How far would Hitler have gone? Could someone stop him?
Personally, I feel that the Third Reich would have collapsed. Although, its downfall would come from within not without. Hitler would probably have died in the late forties and those around him would have fought for power, bringing Germany to its knees. At this point The French Resistance etc. would have secured independence and the last of the Soviets, hiding out beyond the Urals, would have been able to retake Moscow. Germany would grow overall, and this state of affairs could last quite a while, leaving Germany as the most powerful nation in Europe. Not an empire to last a thousand years, but not bad.