GUAIRA FALLS

Portuguese Salto Das Sete Quedas, Spanish Salto Del Guair, former waterfalls on the Upper Paran River at the BrazilParaguay border, just west of Guara, Brazil. Visited by Jesuit missionaries in the 16th century, the falls were supposedly named for a Guaran Indian chief. Although the Brazilian name referred only to seven (sete) falls, meaning the seven principal cataracts, there were actually 18. The falls, which had a total drop of about 375 feet (114 m), were formed when the Paran River, after crossing the red sandstone Maracaju (Mbaracay) Mountains, was forced through canyon walls and narrows abruptly from a width of 1,250 feet (381 m) to 200 feet (61 m). The churning water created a deafening noise that could be heard for a distance of 20 miles (32 km). A constant rainbow hovered over the site. The falls, which were a tourist attraction for many years, probably represented the greatest volume of falling water in the world. Paraguay and Brazil together undertook the building of the 12,600-megawatt Itaipu hydroelectric plant nearby, which was completed in 1982 and totally submerged the falls, thus creating a new reservoir covering an area of 521 square miles (1,350 square km). The Itaipu complex of dams and spillway curves almost 5 miles (8 km) across the Paran River and is one of the world's largest hydroelectric plants.