5 Pesos Carlos J. Finlay

Carlos Juan Finlay, the Cuban physician who first proposed in 1881 that yellow fever was transmitted by the Aedes aegypti mosquito, spent nearly two decades being dismissed by the international medical establishment before Walter Reed's 1900 commission vindicated his theory entirely — using his own experimental methodology. Cuba had been issuing commemorative silver in his honor since the 1950s, and by 1988 the Banco Nacional was producing these pieces almost exclusively for the hard-currency export market, with negligible domestic circulation.