Which World War 1 battle was the deadliest?

Related questions

1. Why did the US not enter ww1?
2. What were the worst battles in ww1?
3. What were tanks originally called?
4. Did Churchill invent the tank?
5. How many deaths in the Battle of Tannenberg?
6. How were ww1 battles fought?
7. How many tanks did Britain have 1939?
8. What battles were tanks used in ww1?
9. How many British tanks were made in ww1?
10. What were the major battles in World War 1?

Tags

1. #battlefield
2. #largest
3. #slaughter
4. #several
5. #destructive
6. #unprecedented
7. #combination
8. #bloodiest
9. #world
10. #battle
11. #failures
12. #leaders
13. #british
14. #after
15. #history
16. #human
17. #modern
18. #compact
19. #among
20. #young
21. #military
22. #somme
23. #weaponry
24. #battles