Surrounding the relatively flat prairie valley where La Crosse lies are towering 500-foot bluffs, one of the most prominent of which is Grandad Bluff (mentioned in "Life on the Mississippi" by Mark Twain), which has an overlook of the three states region. This feature typifies the topography of the Driftless Area in which La Crosse sits. This rugged region is composed of high ridges dissected by narrow valleys called coulees, a French term. As a result, the area around La Crosse is frequently referred to as the "Coulee Region".