10. Invading Russia In Winter
Invading Russia in general has not tended to be a historically good idea. Doing so in winter has almost reached the same meme status as starting a land war in Asia due to the number of times it has been attempted and the percentage of those that have resulted in crushing defeat.
The enemy has never just been the Red Army. It is the bitter and unforgiving Russian winter that is harsh beyond all description to those without first hand experience. Men were dropping like flies from the cold, the exposure and the unrelenting, bleak frozen tundra that they had to march, fight and transport equipment across. The Battle of Stalingrad has been particularly noted as a place of horrendous loss of life. Soldiers on both sides dug in and lives were lost by the thousands. Russian soldiers were sometimes equipped in only cardboard footwear and regularly took the boots of dead Germans to better protect themselves.
This was where the tide was potentially turned and the German army began to be pushed back towards the Fatherland, mile by bloody mile, and the cold and ice certainly did them no favours.