Chinese river embankments. 18th-century map showing rivers in China, with markings showing where embankments, sluice gates and bridges have been built. North is at bottom, with Luomahu Lake (in Jiangsu province) at lower right. A fortress is also shown at upper left. The area shown is called Yuwangtai (King Yu's Terrace), and is part of a series of maps showing the embankments in an old set of waterways associated with the Yellow River. The embankments are shown by red lines. These defences protect people against floods of the Yellow River which have killed millions. This map dates from some time after 1745 during the Qing Qianlong period.