One of the most important technological revolutions in human history began on few islands located near Peru. Droppings deposited here millions of birds have become the element that was the basis for a revolution in agriculture has allowed mankind to overcome for the first time hunger trap. What were the Incas called "guano" (ie manure) would become one of the most important resources of the nineteenth century, being sought by the great nations of the planet with the same zeal with which oil is game day.
