23 October 1942
After various North African operations late in June and in July 1942, Lt.-Gen. B.L. Montgomery, the new commander of the Eighth Army in World War 2, initiated a second attack at El Alamein, a town in northern Egypt on the Mediterranean Sea coast. Many South African soldiers took part in the operation, which started at 9:30pm. South African artillery alone fired 62 000 25-ponder shells. The battle lasted from 23 October to 4 November 1942, when Montgomery finally broke through the defences of the Panzer Army Africa, under command of General Erwin Rommel. Success in the battle turned the tide in the North African Campaign and marked the end of Axis expansion in Africa. 734 South African soldiers were killed at El Alamein.
References

Potgieter, D.J. et al. (eds) (1970). Standard Encyclopaedia of Southern Africa, Cape Town: NASOU, v. 11, p. 518.|

Hickman K. "World War II: Second Battle of El Alamein", From About Military History [online] Available at: www.militaryhistory.about.com [Accessed on 9 November 2012]