Centro Hidroeléctrico de Itaipú
South America's great engineering marvel is the world's largest hydroelectric facility, and spans the Paraná river between Paraguay and Brazil. Construction on the dam, as tall as a 65-story building, was completed in 1984. The installation supplies 19% of Brazil's power needs and an astounding 91% of Paraguay's. Admission is free from the Paraguayan side. (The visitor center on Brazil's side charges for visits.) Take in an informative 90-minute tour and/or a spectacular sound-and-light show on weekend nights.