Farmers in the nineteenth and early twentieth centuries, driven by the American agricultural expansion aggressively took advantage of the land and set up the region for ecological disaster. Most early settlers used the land for livestock grazing until agricultural mechanization combined with high grain prices during World War I motivated farmers to plow up millions of acres of natural grass cover to plant wheat. Tons of topsoil was blown off barren fields and carried in storm clouds for hundreds of miles. For the most part, the driest region of the Plains southeastern Colorado, southwest Kansas and the panhandles of Oklahoma and Texas became known as the Dust Bowl, and many dust storms started there. But the entire region, and eventually the entire country, was affected. For eight years dust blew on the southern plains. It came in a yellowish brown haze from the South and in rolling walls of black from the North. The simplest acts of life breathing, eating a meal, taking a walk were no longer simple. Children wore dust masks to and from school, women hung wet sheets over windows in a futile attempt to stop the dirt, farmers watched helplessly as their crops blew away.