The Nature Conservancy of Minnesota has nearly doubled its holdings with the purchase of 25,000 acres in Northern Minnesota. While it is now prairie, gravel and wetlands, the conservation group's new land once was completely underwater, part of the Lake Aggasiz lakebed. Aggasiz was huge, three times the size of Lake Superior. It covered parts of what is now Minnesota, the Dakotas and Canada. When it drained, the Aggasiz shoreline became wetlands and prairies. "Glacial Ridge," as the Nature Conservancy is calling its new purchase, was part of that former shoreline. Rob McKim, the State Director of the Minnesota Nature Conservancy, says that the area is important because it connects other wildlife management areas, and because Aggasiz left behind a unique topography.