Lucky number 18 for Itaipu Dam

Apparently 18 was a lucky number for engineers working on the Itaipu Dam. The 4.8-mile-long complex of concrete and rockfill dams on the Upper Parana River at the Brazil-Paraguay border has 18 generators, and it took 18 years and $18 billion to build. (Though they have added 2 new generators in the last couple of years!)