The article states that the Great Lakes were created by glaciers scouring the land, and while that is true, I think it more accurate to say that the Great Lakes were caused by a failed continental rift. The Midcontinent Rift System formed a billion years ago and almost tore the North American craton apart, but after 15-20 million years it stopped and faded. The rift filled with sediment that was easy for the glaciers to scour away.

The article links to another Atlas Obscura article about how the Red Sea is debatably a sea or an ocean, because it fills part of the East African Rift System. If we're going to refer to that distinction, then please also mention that the glaciers could scour out a lakebed because ancient geology created it!