The Poverty Point site earthworks were the largest in North America when they were built, from 1700 B.C. to 1100 B.C. Their huge size and complexity indicate that the inhabitants were settled even though they were hunter-gatherers, and also that the population here was very large for a people that did not practice agriculture. The gigantic Mound A stands to the west, and the semi-circular ridges lie in front of the mound, with two ridges in the open area before the trees. The pattern of the ridges was not known until 1952, when James Ford acquired an aerial photograph of the area. The inner ridge, ridge 1, is 1,950 feet in diameter, and the outer ridge, ridge 6, is nearly three quarters of a mile in diameter, surrounding a 43 acre central plaza area.