The thirteen hundred kilometre Rio Iguazu flows into the Rio Parana, the third largest major river of South America where, on the border between Brazil and Paraguay, one of the largest hydroelectric power plants on earth was built, the Itaipu Dam. Tall tubes lead the dam’s water to the turbines and it has been calculated that around forty times the entire water mass of the awesome Iguazu Waterfalls passes through. Each year eighteen generators produce around seventy five billion kilowatt-hours of electricity mainly to supply Sao Paulo and Minas Gerais in Brazil. A work force of up to thirty thousand took part in the creation of this gigantic project and it is thought that the amount of concrete that was used in its construction was enough to rebuild the whole of Rio De Janeiro! It is almost eighteen kilometres long and has a height of a hundred and ninety six metres. The Itaipu Dam and adjoining hydroelectric plant are indeed a remarkable architectural wonder of the twentieth century. The force of nature tamed by Man!