Amazon, Brazil: at the confluence of Rio Negro and Rio Jaú there are ruins of a small town called Airão. Founded by Portuguese missionaries in 1694, Airão concentrated the entire rubber production in the region. After rapid and unsustainable economic growth, followed by the decline of the Rubber Cycle, the city went bankrupt. A politician at the time said that the population was being eaten by ants. Ruined, Airão was abandoned.