What challenges did Hitler face when trying to defeat the Russians?

As the German armies swept further into the Russian heartland, one million Soviet troops were drafted to protect Kiev. But despite Stalin's ruthless order forbidding any city to surrender, Kiev fell and 600,000 Soviet soldiers were captured. By October 1941, three million Soviet soldiers were prisoners of war. New testimony and documentary evidence can now reveal that Stalin was seriously considering suing for peace and had even organised a 'getaway' train to take him to safety as German guns started pounding Moscow. His decision to stay an

Explanation:

the tallest building in the western hemisphere and the sixth tallest building in the world