The Red River Valley, glacial Lake Agassiz. For many among us, that probably brings to mind rich farmland and perhaps a finger shaped lake from the end of the last ice age that covered the area along North Dakota/Minnesota border. It would have been fifty miles wide or so, with the southern end in bit south of where North and South Dakota meet Minnesota. The northern end would have been, well, not sure. At the margin of the glacier, somewhere up by Winnipeg, maybe.