The massive fluctuations that El Nino causes in the world's weather systems have changed the course of history. Unusually cold winters and the resulting poor crops helped forment the French Revolution. Hitler's march across Russia was halted by one of the harshest winters on record. Severe drought in India in 1877 killed millions while a drop in sea temperatures, leading to dwindling food stocks, precipitated the fall of the mighty Aztecs. Would these events have happened without the impact of El Nino?