Water From the beginning, water has furnished man with a source of food and a highway to travel upon. The first(51) arose where water was a dominant element in the environment, a challenge to man's ingenuity. The Egyptians invented the 365-day calendar(52) the Nile's annual flooding. The Babylonians, who were among the most famous law-makers in ancient times, invented laws(53) water usage. Water inspired the Chinese to build a 1,000-(54) canal, a complex system which, after nearly 2,500 years, remains still practically(55) and still commands the astonishment of engineers. But the(56) never found complete solutions to their water problems. The Yellow River is also known(57) 'China's Sorrow'; it is so unpredictable and dangerous(58) in a single flood it may cause a million(59) . Floods slowed the great civilization of the Indus River Valley, and inadequate drainage ruined(60) its land. Today water dominates(61) as it always has done. Its presence continues to(62) the location of his homes and cities; its violent variability can(63) man or his herds or his crops; its routes links him(64) his fellows; its immense value may(65) to already dangerous political conflicts. There are many examples of this in our own time.