While the paintings are thought to be around 3,000 years old, no one is exactly sure. Anywhere between 1,000 and 4,000 years is plausible, and the art was probably added gradually over a lengthy period of time. The artists are thought to have used palm leaves to apply the natural paints, mostly red but also with some black and white. Much of the cliff face overhangs, sometimes dramatically, as softer shales compose the lower strata that are capped by less easily eroded sandstone.