What contributed to the battle of stalingrad becoming a turning point in the war?

I can see two main points that shows the importance of the Battle of Stalingrad:
1] Material: In the battle the Germans lost and entire army (the 6th) with its entire staff of commanding officers including a Field Marshall (von Paulus). This was a staggering loss for a country of limited possibilities in replacing manpower.
2] Psychological: For the first time (and from here on throughout the entire war) the Russian Red Army assumed the initiative in conducting offensive actions. The fact also that the first big defeat in Russia of the German Army happened in a town with the name of Stalin didn’t help the morale.

Ithink it was the jungle