Casa Milà, better known as La Pedrera, meaning the 'The Quarry', is a building designed by the Catalan architect Antonio Gaudi and built during the years 1905–1910, being considered officially completed in 1912. It was a controversial design at the time for the bold forms of the undulating stone facade and wrought iron decoration of the balconies and windows, designed largely by Josep-Maria Jujol who also created some of the plaster ceilings. Architecturally it is considered an innovative work for its steel structure and curtain walls – the facade is self-supporting. Other innovative elements were the construction of underground car parking and separate lifts and stairs for the owners and their servants. In 1984, it was declared World Heritage by UNESCO.