Built of reinforced concrete, the building was soon nicknamed “La Pedrera” -- the Stone Quarry -- because it appeared to be carved out of rock. Casa Mila is, in fact, two apartment buildings joined at the corner diagonal. It was commissioned by the industrialist Pere Mila and his wife, who lived on one floor and rented out the rest of the building to their friends. In 1986, La Caixa bought and restored the building; it is now a cultural space.