3500 BCE are the only ones known to have been built by a hunter-gatherer culture, rather than a more settled culture based on agricultural surpluses. The best-known flat-topped pyramidal structure is Monks Mound at Cahokia, near present-day Collinsville, Illinois. This community was the center of Mississippian culture. This mound appears to have been the main ceremonial and residential mound for the religious and political leaders; it is more than tall and is the largest pre-Columbian earthwork north of Mexico. This site had numerous mounds, some with conical or ridge tops, as well as palisaded stockades protecting the large settlement and elite quarter. At its maximum about 1150 CE, Cahokia was an urban settlement with 20,000–30,000 people. This population was not exceeded by North American European settlements until after 1800. Some effigy mounds were constructed in the shapes or outlines of culturally significant animals. The most famous effigy mound, Serpent Mound in southern Ohio, ranges from to just over tall, wide, more than long, and shaped as an undulating serpent. Early descriptions Between 1540 and 1542, Hernando de Soto, the Spanish conquistador, traversed what became the southeastern United States. There he encountered many different mound-builder peoples who were perhaps descendants of the great Mississippian culture. De Soto observed people living in fortified towns with lofty mounds and plazas, and surmised that many of the mounds served as foundations for priestly temples. Near present-day Augusta, Georgia, de Soto encountered a group ruled by a queen, Cofitachequi. She told him that the mounds within her territory served as burial places for nobles. The artist Jacques le Moyne, who had accompanied French settlers to northeastern Florida during the 1560s, likewise noted Native American groups using existing mounds and constructing others. He produced a series of watercolor paintings depicting scenes of native life. Although most of his paintings have been lost, some engravings were copied from the originals and published in 1591 by a Flemish company. Among these is a depiction of the burial of an aboriginal Floridian tribal chief, an occasion of great mourning and ceremony. The original caption reads: Maturin Le Petit, a Jesuit priest, met the Natchez people, as did Le Page du Pratz (1758), a French explorer. Both observed them in the area that today is known as Mississippi. The Natchez were devout worshippers of the sun. Having a population of some 4,000, they occupied at least nine villages and were