Columbus discovers America!

I was watching Marr's excellent "History of the World" on BBC tv - http://www.bbc.co.uk/iplayer/episode/p00xnrqg/Andrew_Marrs_History_of_the_World_Age_of_Plunder/, when it struck me that if ever there was a good example of the Law of Unintended Consequences, it was the so-called discovery of America by Christopher Columbus.  


Columbus was seeking the Far East by sailing west to cut short the multi-thousand mile land journey across deserts and mountains and through fierce-some tribes and brigands. Instead he found the new continent.  The unintended consequences go far beyond the mere discovery, it provide the 'old world' with staple foods like the potato and maize and the narcotic tobacco. It also meant over the next few century the devastation to the populations of South America, the Incas and the Mayans were wiped out by war and disease and the north American Indians met with no better fate. Followed by the enslavement of vast populations of east Africans.