In physical geography, an oasis is an isolated area of vegetation in a desert, typically surrounding a spring or similar water source.
The location of oases has been of critical importance for trade and transportation routes in desert areas. Caravans must travel via oases in order that supplies of water and food can be replenished. Thus, political or military control of an oasis has in many cases meant control of trade on a particular route. For example the oases of Awjila, Ghadames and Kufra, situated in modern-day Libya, have at various times been vital to both North-South and East-West trade in the Sahara desert.