Complex sentence: It is probably the best natural port in northern Africa, although due to the lack of important nearby land sites it is certainly not the most popular: the city is effectively surrounded by a desert lightly populated with nomadic herdsmen who travel from oasis to oasis.
Split into simpler sentences: It is probably the best natural port in northern Africa, although due to the lack of important nearby land sites it is certainly not the most popular. The city is effectively surrounded by a desert lightly populated with nomadic herdsmen who travel from oasis to oasis.