II.

Prehistoric Earthwork Architecture

Indigenous peoples lived in North America for thousands of years before Europeans arrived. Their early structures included earth mounds that provided elevated bases for residences of rulers and pedestals for temples and other sacred architecture. The houses or temples, built of wood and often covered with thatched roofs, disappeared hundreds of years ago. Some of the mounded earth constructions remain, although diminished by thousands of years of erosion.

The earliest known enclosures built in North America are rings of mounds constructed in what is now Louisiana and lower Arkansas, from as early as 6,500 years ago to as late as 3,000 years ago. The largest of these structures—built about 5,400 years ago near Monroe, Louisiana—is a group of 11 mounds in an oval ring that measures roughly 200 by 260 m (650 ft by 850 ft). Monumental earth architecture was built by hunter-gatherer cultures in North America nearly 1,000 years before the Great Pyramids in Egypt.

From about 1700 bc to 700 bc, a second major period of mound building flourished, again concentrated along the Mississippi River in northern Louisiana, though its influence extended as far as central Texas, Arkansas, southern Missouri, and Indiana. This period of mound building seems to have had its center in a place today called Poverty Point, near Epps, Louisiana. The Poverty Point culture, responsible for building these mounds, is named after this site. The enormous complex at Poverty Point consists of six low, concentric rings of mounded earth with a large plaza at their center. The largest, outer ring measures about 1,200 m (nearly 4,000 ft) in diameter, and the plaza has a diameter of 181 m (about 595 ft). To the west of the rings stood a large mound, which today rises 20 m (66 ft) in height and extends more than 200 m (660 ft) in length. Nothing on this scale would be built in North America for several more centuries. See also Poverty Point National Monument.

A later mound-building culture, named Adena, arose in Ohio about 1100 bc and spread to Kentucky, Pennsylvania, and New York before it ended about 200 ad. The dome-shaped Adena mounds were used as cemeteries, and rose higher from additional burials over the centuries. Early European and American explorers and settlers failed to appreciate the sacred nature of these burial mounds, and plundered and obliterated thousands of mounds. Other mounds slowly disappeared after generations of farmers repeatedly plowed them.

Another mound building culture, named Hopewell, also appears to have originated in Ohio but expanded west to Iowa, Kansas, and Oklahoma, south to Louisiana, Mississippi, and Alabama, east to Georgia and the Appalachian Mountains, and north to Wisconsin, Michigan, and lower Ontario in Canada. The Hopewell culture lasted from about 200 bc to 400 ad. Hopewell people built large, linear mounds to create enclosures in geometrical shapes, such as squares, circles, and octagons. Over time the Hopewell mounds extended outward in clusters, rather than upward as the Adena mounds did. The Hopewell mounds are especially significant because many of the forms are aligned with specific stars, solar events, or points on the horizon where the moon rises and sets. Awareness of astronomical cycles appears to have been highly important to the people.

Effigy mounds, built during and after the Adena and Hopewell culture periods, took the form of animals and human beings. The Serpent Mound in southern Ohio has a long wavy body about 382 m (1,254 ft) long and today rises about 1.2 m (4 ft) high. It was built about 1100 AD atop a bluff. The folds in its undulating body align in direction with the solar solstices and equinox.

The final mound-building culture, called Mississippian, flourished in the Mississippi River valley from about 800 ad to the mid-1500s. The mounds in some areas were still in use when Europeans ventured into North America. The mounds had square or rectangular bottoms and sloping sides that rose to broad flat tops or terraces. Residences of nobles or temples topped many of these mounds. Mississippian mounds, unlike the mounds of the Adena and Hopewell cultures, appeared near permanent settlements. Excavations at the largest Mississippian town—at Cahokia, Illinois—suggest that its native population once numbered perhaps 30,000 people and that about 120 mounds once stood there. The town’s central ceremonial plaza measured 5.6 by 3.6 km (3.5 by 2.25 mi), and a large adjacent mound, today called Monks Mound, rose through several terraces to a height of nearly 30 m (100 ft), dominating the countryside for miles around.