The North American Great Lakes- Huron, Ontario, Michigan, Erie, and Superior- are so big that they border 8 states and contain 23 quadrillion liters of water. They span forest, grassland, and wetland habitats, supporting a region that's home to 3,500 species. Cheri Dobbs and Jennifer Gabrys takes us all the way back to the Ice Age to find out the history of these lakes. [4:47]