Columbus is one of Georgia's three Fall Line Cities, along with Augusta and Macon. The Fall Line is where the hilly lands of the Piedmont plateau meet the flat terrain of the coastal plain. As such, Columbus has a varied landscape of rolling hills on the north side and flat plains on the south. The fall line causes rivers in the area to decline rapidly towards sea level. Textile mills were established here in the 19th and early 20th centuries to take advantage of the water power from the falls.