Callao is a station on Line 3 and Line 5 of the Madrid Metro. It is located in fare Zone A. It is named after the Plaza del Callao, under which it is located.
Wikipedia https://en.wikipedia.org/wiki/Callao_(Madrid_Metro)
Address 46 Calle Gran Vía, Madrid 28013, Spain
Coordinates 40°25'13.381" N -3°42'22.09" E