Archaeological excavations have revealed the existence of humans in what is now Vietnam as early as the Paleolithic age. ''Homo erectus'' fossils dating to around 500,000 BC have been found in caves in Lạng Sơn and Nghệ An provinces in northern Vietnam. The oldest ''Homo sapiens'' fossils from mainland Southeast Asia are of Middle Pleistocene provenance, and include isolated tooth fragments from Tham Om and Hang Hum. Teeth attributed to ''Homo sapiens'' from the Late Pleistocene have been found at Dong Can, and from the Early Holocene at Mai Da Dieu, Lang Gao and Lang Cuom. By about 1,000 BC, the development of wet-rice cultivation in the Ma River and Red River floodplains led to the flourishing of Đông Sơn culture, notable for its bronze casting used to make elaborate bronze Đông Sơn drums. At this point, the early Vietnamese kingdoms of Văn Lang and Âu Lạc appeared, and the culture's influence spread to other parts of Southeast Asia, including Maritime Southeast Asia, throughout the first millennium BC.