Because of its sheer size and the erosion from centuries of wind and rain and other damaging factors, it is hard to realize exactly what you are seeing and what it was like when built. On the grounds near the visitors center is a scale model of the entire site. This will give you a good idea what the site was designed to look like.
One of the most interesting aspects of the site, at least to me, is Mound A which is shaped like a bird in flight. This is the largest of the mounds and is still over twenty feet high after centuries of erosion by the weather. It is believed this mound was used as a platform for religious ceremonies. There is a stairway to the top of the mound and the tram will stop here for you to climb it if you ask.
The central construction consists of six rows of concentric ridges, which at one time were five feet high. The five aisles and six sections of ridges form a partial octagon. The diameter of the outermost ridges measures three-quarters of a mile. These rows were formed around a centralized area like a plaza. It is thought that these ridges served as foundations for dwellings although little evidence of structures has been found. Some of the features, and trash and debris found here support this theory. This society also imported items from as far away as the Ouachita and Ozark Mountains, the Ohio and Tennessee River valleys, and the Appalachian foothills of northern Alabama and Georgia.