The cause of a massive electrical blackout that darkened large portions of Brazil in early November is still being investigated despite initial reports from the national grid operator that lightning and strong winds affected the transmission grid in southern Brazil. Photo: Germano Luders Itaipu hydro plant, on the border of Paraguay and Brazil, stayed in operation following Nov. 10 storms, officials say. Transmission lines serving the Brazilian grid did not fare as well. At 10:13 p.m. on Nov. 10, the lights went out in Brazil. For almost three hours a massive swath of the South American country, including 18 of
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.