Via the Imperial War Museums. The Q should be, not why he invaded Russia, but didn’t invade Russia first and leave western Europe alone? Had he done that, he may have succeeded in his goals of expanding Germany. Western Europe would have strongly objective for sure, but would not have gone to war for a communist country like Russia. Maybe the world is better off he didn’t take that approach? The costs in lives is incomprehensible at as a result of the approaches he did take.
how would he get around Poland, though? Remember, they’re allies with UK and FR and as soon as one piss-sucking Nazi jackboot crosses the frontier Game On… bypass Poland and take the long way around through Ukraine?
Russia was hopelessly there like ripe fruit for Hitler, so tempting but, he really needed to secure the entrance to the Medeterrainian before dreaming so big as to invade Russia.
The Med, then the Oil Fields in the ME, which for the most part isn’t enough to goiad US participation in the War, but certainly set Hitler up for better things..
Edit to add being alligned with Japan was a millstone around Hitlers neck.