The Palaeolithic, (or Paleolithic), refers to the prehistoric period when stone tools were made by humans. They are found in the Great Rift Valley of Africa from about 3.3 million years ago. They were probably made by Australopithecines. They are found in Europe somewhat later, from about 1 mya (0.7mya for Britain). The Palaeolithic is by far the longest period of humanity's time, about 99% of human history. The geological period which corresponds to the Palaeolithic is the Pleistocene.