Why did Battle of Stalingrad happen?

Related questions

1. What was Stalingrad original name?
2. Why did Germans surrender?
3. Is Leningrad and Stalingrad the same place?
4. How long did the Battle of the Bulge last?
5. How many died at Stalingrad?
6. Which is the bravest battle ever fought?
7. Why is the Battle of Stalingrad important?
8. How cold was the battle of Stalingrad?
9. Who won the battle of Stalingrad?
10. Why did the Battle of Stalingrad happen?

Tags

1. #during
2. #winter
3. #battle
4. #reason
5. #fields
6. #primary
7. #target
8. #saved
9. #germans
10. #caucasus
11. #paulus
12. #ordered
13. #stalin
14. #stalingrad
15. #secure
16. #hitler
17. #final
18. #fought