Atapuerca fossil excavation. Researcher excavating human and animal fossils from the TD-10 level in the Gran Dolina site in the Sierra de Atapuerca foothills near Burgos, Spain. The Atapuerca fossil sites are a UNESCO World Heritage Site, containing the earliest human remains found in Europe. The TD-10 level (450,000 years old) contains fossils of Homo heidelbergensis (Heidelberg Man), an extinct hominin species from the same genus as modern humans. Like other early humans, they had complex social structures and lived in family groups. They lived around 600,000 to 400,000 years ago.