Peking Man is a subspecies of H. erectus which inhabited the Zhoukoudian cave site in modern northern China during the Chibanian. The first fossil, a tooth, was discovered in 1921, and the Zhoukoudian cave has since then become the most productive H. erectus site in the world. Peking Man was instrumental in the foundation of Chinese anthropology, and fostered an important dialogue between Western and Eastern science for decades to come. The fossils became the centre of anthropological discussion, and were classified as a direct human ancestor, propping up the Out of Asia hypothesis that humans evolved in Asia.