-Initial attack on Russia, breaking the Non-Aggression Pact on June 22, 1941
-Stalin was caught off-guard
-Germans get within 50 miles of Moscow, the Russians retreat to Moscow and instate Scorched Earth Policy
-Russian winter hits, coldest in 50 years
-German weapons freeze up and thousands died to cold
-Attack on Moscow failed, Siberian soldiers and weather primary reason.
Summary
Due to having to bail Italy out of getting invaded, Germany's plans got pushed back a few months. This made them attempt to take over Moscow in the winter, which they were not prepared for.