The geological event that most contributed to the development of Iowa's physical characteristics is the Wisconsin Glaciation, which occurred around 14,000 to 10,000 years ago. During this period, massive glaciers covered much of North America, including Iowa. The movement of these glaciers reshaped the landscape of Iowa, carving out the unique rolling hills, valleys, and plains that characterize the state today. The glaciers also deposited layers of sediment and left behind numerous lakes, rivers, and wetlands that contribute to the state's diverse ecosystem.
