National Geographic : 1930 Sep
MASTERLY ENGINEERING FEATS BY UNTUTORED PAGANS EUILT THE RICE TERRACES INTHE MOUNTAINS OFLUZON In the subprovince of Ifugao about 132,000 primitive tribesmen live on a plane area of 750 square miles,less than one-fifteenth ofwhich iscultivated. This means that more than 2,000 people derive subsistence from each section of tilled ground. Working with wooden shovels, these natives have erected around their garden patches walls of dirt and stone a foot or more thick and often 40 feet high-walls which ifplaced end toend would extend half around the world at the Equator. The enclosures contain mud and water in exactly the right proportion,and aresoconstructed that excess water passes immediately to lower levels, where it is needed.