Codirector of the Atapuerca project Jose Mar韆 Berm鷇ez de Castro (right in green shirt) and palaeontologist and co-ordinator of Sima del Elefante archaeological site Rosa Huguet (front left) presenting a hominid jawbone fossil discovered at the Sima del Elefante archaeological site, Spain. The jawbone is thought to be the oldest discovered remains of a human ancestor in Europe. Sima del Elefante site is located in the Trinchera del Ferrocarril, a trench that was dug in the foothills of Sierra de Atapuerca at the end of the 19th century. As well as a rich collection of mammal fossils dating back to between 1.25 and 1.5 million years, stone tools have been found at this site. The extensive discoveries at the Atapuerca sites have led to numerous advancements in the understanding of human evolution.