The landscape of the Netherlands is a man-made, cultural landscape, mainly flat, apart from regions in the eastern and southern extremities, lying between -6 and 20 meters above sea level. Since the beginning of the last millennium, settlers, farmers, city dwellers and engineers have created a system of dykes, barriers and locks defending a part of the inner land, as well as the coastline of the whole country. The abundance of land units with a man-controlled water level has made the word "polder" a Dutch contribution to many languages of the world.