Researchers assembling a fossilized male Homo heidelbergensis pelvis, nicknamed Elvis with its five lumbar vertebrae for display at the Museum of Human Evolution in Burgos, Spain. The fossilized pelvis and vertebrae were both found at the Sima de los Huesos (Pit of Bones). Sima de los Huesos is one of several sites in Sierra de Atapuerca, Spain, that have been studied on and off over the past century, leading to a massive advancement in the understanding of human evolution. In 2000, Sierra de Atapuerca was made a world heritage site by UNESCO.