The Itaipu dam, built on the Paraná River (which forms the border between Brazil and Paraguay), is the biggest dam and the biggest hydroelectric power plant in the world. It's also one of the "seven wonders of the modern world". With 20 turbine generators, and a dam wall almost 8km long, the plant supplies a whopping 90% of Paraguay's electricity, as well as 25% of Brazil's. Thus, most ironically, Paraguay — otherwise one of the most backward s$%#-holes in South America — has virtually the greenest energy in the entire world. This afternoon, Annemie, Hendrik and I went on a tour of the dam, and we saw this monster feat of modern engineering in action.