Complex sentence: The Second Battle of El Alamein took place over 20 days from 23 October--11 November 1942 near the Egyptian coastal city of El Alamein, and the Allies' victory marked a major turning point in the Western Desert Campaign of the Second World War.
Split into simpler sentences: The Second Battle of El Alamein (23 October--11 November 1942) took place near the Egyptian coastal city of El Alamein. With the Allies victorious, it marked a major turning point in the Western Desert Campaign of the Second World War.