The Hoover Dam

de bene esse: literally, of well-being, morally acceptable but subject to future validation or exception

There is enough concrete in the Hoover Dam to build a 4 ft. wide sidewalk around the earth at the equator. It was an enormous, nature-defying endeavor.

Learn about its history and construction: http://s.si.edu/10MxPGi thanks to Smithsonian Channel.