Cahokia Mounds

These grass-covered mounds are not just part of a pretty outdoor park they are actually the remnants of an ancient pre-Columbian Native American city that dates back over 1,000 years. This 2,200-acre site has approximately 80 different manmade mounds that were used as temples, residences, and mass burial grounds, making it the largest and most sophisticated prehistoric site north of Mexico. Although these structures suggest that it was home to a flourishing civilization, little is known about the day-to-day life of the people who lived here. Archeologists have also found artifacts, statues, and other relics that were buried around the ancient city. Even if you are not into history, this spectacular site will wow you. It is simply one of those must-see places you should add to your itinerary.