Complex sentence: The LRDG area of operations between 1940--1943 was the Libyan desert, which stretches about south from the Mediterranean to the Tibesti and the Jebel Uweinat mountains, and about from the Nile valley in the east to the mountains of Tunisia and Algeria in the west.
Split into simpler sentences: The LRDG area of operations between 1940--1943 was the Libyan desert. Which stretches about south from the Mediterranean to the Tibesti and the Jebel Uweinat mountains and about from the Nile valley in the east, to the mountains of Tunisia and Algeria in the west.