This model takes its shape from Twiggy’s cranium. Scientifically known as OH24 skull, it belongs to the species Homo habilis, which is between 2.3 and 1.6 million years old. It was found at the Olduvai Gorge site, in Tanzania. The cranial capacity of this species is between 510 and 800cc (our species, Homo Sapiens, has an average of 1300cc).