Aztalan State Park is a National Historic Landmark and contains one of Wisconsin's most important archaeological sites. It showcases an ancient Middle-Mississippian village that thrived between A.D. 1000 and 1300. The people who settled Aztalan built large, flat-topped pyramidal mounds and a stockade around their village. Portions of the stockade and two mounds have been reconstructed in the park. Aztalan State Park is open year-round from 6 a.m. to 10 p.m.