the largest project of this type in the world has been in process for centuries in the netherlands. the area between amsterdam, haarlem and leiden was, in prehistoric times swampland and small lakes. turf cutting (peat mining), subsidence and shoreline erosion gradually caused the formation of one large lake, the haarlemmermeer, or lake of haarlem. the invention of wind powered pumping engines in the 15th century permitted drainage of some of the marginal land, but the final drainage of the lake had to await the design of large, steam powered pumps and agreements between regional authorities. the elimination of the lake occurred between 1849 and 1852, creating thousands of km2 of new land.