Watson Brake, in northern Louisiana, is the oldest example of the mound-building cultures that would come to dominate the Mississippi river basin. Initiated in around 3500 BCE, 11 mounds form an oval 900 feet (274 m) across. Nearby Poverty Point represents the apogee of this early phase, with six massive concentric crescent earthworks enclosing a plaza and traversed by avenues linking central and external mounds. Remains there indicated a hunter-gatherer way of life, with extensive inter-regional trade networks. The next major flowering would occur in the Adena area of the Ohio River valley. Foraging was now supplemented by the cultivation of pumpkins, squash and goosefoot. The characteristic mound shape was conical, but a number were effigies of mammals, birds and snakes. The Hopewell culture extended (through a series of connecting sub-cultures) from the Gulf of Mexico to the Great Lakes. Now sedentary, farming maize, this tradition produced flat-topped pyramids and vivid figurative artwork.