The Monks Mound is the largest pre-Columbian earthwork in the Americas and the largest pyramid north of Mesoamerica. In 1988, Monk Mound was about 100 feet in height and 955 feet long. The Mound is located at the Cahokia Mounds UNESCO World Heritage Site near Collinsville, Illinois.
The Monks Mound base circumference is larger than the Pyramid of the Sun at Teotihuacan and roughly the same size as the Great Pyramid of Giza (13.1 acres). However, Egyptian pyramids built with stones, in contrast to the platform mounds, were constructed entirely of layers of basket-transported soil and clay. Due to the flattened top, the rainwater accumulated within the structure results in slumping, the avalanche-like sliding of large sections of the sides at the highest part of the mound.
The recent excavations have exposed the slumping problem, though the mound was being made. These days, researchers are stunned by how native engineers built Monk’s Mound, and their findings conclude that the massive earthwork may have been built surprisingly fast, maybe in just a fraction of the time that archaeologists once thought. Monks Mound is an extremely complex bit of earthen architecture, certainly in tune with its materials.
The original concept was a much smaller mound; however, several types of earth and clay from different sources had been used successively. The construction of monks suggests that the stability of the mound was improved by the incorporation of bulwarks, some made of clay, others floodplain, which allowed steeper slopes than the use of earth alone.
Moreover, the structure rises on four terraces containing 22 million cubic feet of adobe, carrying a basket to the site. So, in brief, it took a lot of smarts to build the Monks Mound and have it last for as long as it has.