In 1984, three works by Gaudí, Güell Park, Güell Palace and Casa Milà were all declared World Heritage sites, all located in Barcelona. In 2005 it was decided to extend the title to four other buildings, the set being called "Works of Antoni Gaudí". The last four monuments are the Vicens House, the facade of the Nativity and the crypt of the Sagrada Familia, and the Batlló House, in Barcelona, together with the crypt of Colonia Güell, in Santa Coloma de Cervelló. All these works, according to Unesco, « atests to the exceptional creative contribution of this architect to the development of architecture and construction technology in the 19th and early 20th centuries ».