Car bodies embedded in the cutbanks of streams and rivers to stem erosion are called detroit riprap. The adjective detroit refers, of course, to the American home of car production, Motor City, though the practice of lining up autos nose down and door-to-door in waterways is not limited to the Midwest. Indeed, it was once a popular way, countrywide, to put old cars to use. While car bodies might be cheaper than manufactured materials used in the construction of riprap, abandoned cars, with their residues of grease, paint, oil, and rust, placed in waterways are neither environmentally safe nor sound. The practice is now rare.