☰Itaipú Dam

The second-largest hydroelectric dam on earth (after China's Three Gorges), a 7.9 km wall of concrete across the Paraná river jointly operated by Paraguay and Brazil. It produces about 90% of Paraguay's electricity and a fifth of Brazil's. Free guided tours run several times a day from the visitor centre; the "special circuit" goes inside the turbine hall and is worth the extra fee for the sheer scale of the machinery.