Human evolution and culture were enabled by developments in human anatomy including brain size, vocal tract structure, dexterous hands, and bipedal locomotion. Over time, these biological capacities facilitated increasingly complex stone tool industries that began with Oldowan tools 2.6 million years ago used by Homo habilis. The Acheulean industry begun by Homo erectus 1.5 million years ago featured hand axes. Neanderthals developed the Mousterian industry 300,000 years ago combining Acheulean and Levallois techniques. Later industries like Aurignacian 45,000 years ago showed early symbolic expression through art and materials.