Way back in the early 1500s, there was a war going on between the cities of Pisa and Florence. Both were located along the Arno river, but because Pisa was located farther downstream, it was able to block Florence’s access to the sea. Pisa had geography on its side, but Florence had mind-power. Philosopher Niccolò Machiavelli lived there and, deciding to take matters into his own hands, he began to scheme with a friend of his named Leonardo da Vinci. Da Vinci created detailed maps of the Arno, and came up with a plan for stealing the entire river away from Pisa. But, as was so often the case, Da Vinci was ahead of his time. The laborers who worked on digging the necessary canals could not dig fast enough or deep enough to have an effect. Da Vinci, of course, invented a machine that could do the work more effectively, but it was never built. The Florentines attempted to fix the problems, but a heavy storm destroyed much of their work. By the time they recovered from that, the Pisans were onto their little plot and made sure that no one tried to steal their river again.