The Tolleston Dunes Trail winds amid 4,700 year-old sand dunes that were formed when Lake Michigan's water level was 25 feet higher than today. Tolleston is the second youngest of four distinct dune systems found within the national park. Together these dune ridges provide a glimpse into the changing shoreline of Lake Michigan. Tolleston Dunes has varied habitats ranging from globally rare black oak savanna to wetlands and plants such as prickly pear cactus, butterfly weed, and the wild blue lupine flower (Lupinus perennis) which grows in abundance. Another plant with a large population is the eastern prickly pear cactus (Opuntia humifusa).