Illinois researchers discovered the remains of several earthwork mounds. In the East St. Louis area, 50 mounds had been mapped before the Civil War, and seven remain visible today. The largest is estimated to have been originally 40 feet high and would have nearly covered a football field. Around the remains of this mound, researchers have discovered evidence of burial mounds, a large plaza, a wooden defensive palisade and several other Mississippian culture structures. These indicate that it was a ritual center. The 500-acre prehistoric site is now called the East St. Louis Mound Center. The state and University of Illinois are trying to develop coordinated projects with East St. Louis and businesses to use the mounds and artifacts as attractions for heritage tourism.