You are arriving at Madrid, have a walk through Madrid and comes across this square: Callao what? Spaniards often let a letter, the spoken d, you know: cansado-cansao, alicatado-alicatao, callado-callao, Callao. I thougt. And 'callado/callao' means 'quiet'. But it is not true. There was a battle in Spanish-Southamerican War in 1866, the Battle of Callao, named by the peruan city of Callao. That's it.