Although hominids dating back as far as 1,800,000 B.C. have been found in China to the north and in Indonesia to the south, there have been no such finds in the land that will become Vietnam. Neither are there any finds reported of early (150,000–50,000 B.C.) Homo sapiens in Vietnam, although inasmuch as they were present in southern China some may have lived in Vietnam. Almost certainly by 20,000 B.C., the late Upper Paleolithic, Homo sapiens are living in parts of Vietnam and beginning to develop some distinctive cultural traditions in response to local environment and resources. (Because the sea level has risen greatly since then, it may well have wiped out early coastal sites of these people.) In particular, Vietnam lies in a tropical climate zone, one subject to the monsoon—the annual rainy season alternating with a dry season. Water is plentiful in terms of surrounding ocean, rivers, and annual rainfall. The rainfall also supports a dense forest cover and eventually supports rice cultivation. Not until the Late Paleolithic is a culture known to emerge in Vietnam. For some twenty thousand years, a series of cultural phases would develop in Vietnam; although there is not total agreement on the exact dates, the sequence is generally agreed on. It is also agreed that there will eventually be a mixture of the original Australo-Melanesian inhabitants of Vietnam and the later arriving Mongoloids. The Vietnamese cultures produce several distinctive achievements, yet eventually the more populous and expansive Chinese will move in and take control of Vietnam. Although at this time there is neither a border nor much distinction between “China” and “Vietnam” in this region, the earliest references to the people of Vietnam distinguish them as the Lac. During the third century B.C. the Chinese name for the region and people of southeastern China becomes Yueh, and the name for those still further south becomes Nan Yueh; eventually the order is reversed and the region and people and place are called Yueh Nan; to the people who will become the Vietnamese, Yueh is pronounced Viet and Nan is pronounced Nam, and thus Viet Nam.