Itaipú dam

Located at the Brazilian-Paraguaian border and not far from the Argentinian border, the first step of the initiation was already in 1966 when the Ministers of Foreign Affairs of Brazil and Paraguay signed a joint statement known as the "Act of Ygazu". By this a study and evaluation of the hydraulic resources of the Parana river (owned jointly by Brazil and Paraguay) followed. Is 12 miles north of Foz do Iguazu.
The construction work sarted in 1975, reaching its peak in 1978 with 30 000 people at work. Monthly on-site concrete production reached 338 000 m³. In total, 15 times the mass of concrete used for the "Eurotunnel" was supplied. The height of the dam reaches 196 m, its length 7.76 km. The lake created by this is 170 km long and contains 29 billion tons of water. 
Of the twenty generator units currently installed, ten generate at 50 Hz for Paraguay and ten generate at 60 Hz for Brazil. Two 600 kV HVDC lines, each approximately 800 km long, carry both Brazilian and Paraguayan energy to São Paulo where the terminal equipment converts the power to 60 Hz.