Table Mountain is 1,086 metres (or 1,087 according to some sources) high and is one of the new Seven Wonders of Nature. It is believed to be one of the oldest mountains in the world, lying above ancient shales deposited some 700 million years ago and large areas of granite dating back some 540 million years. The sandstone sediment which forms the main block of the mountain was deposited around 450 million years ago when the peninsula, then a part of Gondwana, lay below sea level. The effects of wind, ice, rain and extreme temperatures caused erosion of the softer layers leaving behind the characteristic mesa.