The colourful Casa de las Bolas, constructed between 1885 and 1895, lies on Calle de Alcalá (Alcalá Street) in the Salamanca District of central Madrid, Spain.

The edifice was designed by Julián Marín and was expanded as well as refurbished a decade after its completion by Luis Sainz de los Terreros Gómez between 1905 and 1906.

It was fashioned in neo-Mudejar style and actually comprises several blocks of houses set on a triangular plot featuring two circular towers on the far ends of its facade on Alcalá Street.