To the south, beyond the Bahariya oasis lies the Black Desert, an area of black volcanic hills and dolerite deposits. Beyond this, north of Farafra, lies the White Desert, an area of wind-sculpted chalk rock formations, which give the area its name. To the south of Kharga the plateau rises towards the Gilf Kebir, an upland region lying astride the Egypt-Sudan border and home to pre-historic sites such as the Cave of Swimmers.