Two places in the world have thick layers of wind-blown material called Loess, Shaanxi, China and Western Iowa. The Loess Hills of Iowa stand up to 200 feet tall, paralleling the Missouri River. Loess, which contains a rich variety of minerals, stands up best in vertical (rather than sloped) road cuts. One such cut is on old Route 6 just east of Council Bluffs, shown in this August 1999 photo.