 In 1942 the archaeologist Mary Leakey discovered prehistoric human artefacts at Olorgesailie, a lower Palaeolithic site southwest of Nairobi.In the mid-1940s she and Louis Leakey excavated the site, and Shackleton collaborated with the investigations, preparing geological maps of the area around the Olorgesailie site and the area between Olorgesailie and Ngong.Shackleton returned to Imperial College in 1945 and was offered a professorship there.