20 Cruzeiros

Brazil's shift to aluminium for this denomination in 1965 was a direct response to chronic inflation eroding the intrinsic value of earlier cupronickel issues — when the metal in a coin approaches its face value, the mint loses the argument for keeping it. The cruzeiro itself was already a dying currency by this point; the military government that had seized power in 1964 would replace it entirely with the cruzeiro novo in 1967, at a conversion rate of 1,000 to 1.