Adolf hitler (why the hell he do it)?

during world war2.german army occupied france in less than a month,soon britan began to fall.after occupying most of europe.why germany attacked.soviet union(russia alone is far more powerful than us.even adolf hitler know it).(in history books it is written.he taught germany can use vast resources of soviet union.).during initial phase of war germany had occupied large russian areas.hitler know about about soviet winter(why he did not supply his troops with winter wear).why hitlers air force luftwaffe unable to destroy weapons factories in interior of soviet union.if germany did not invade soviet union britain would history(since he can use all the weapons and army against it).it would became a major power.but why did he do it killing more than 5million russian men and nearly 1million german men.in the war.please give personal opinions.this question is not to hurt anyone but i am very interested in history.please give your opinions.