La Pedrera is the last great civil work of Antoni Gaudí, a monumental residential building in the Passeig de Gràcia in Barcelona built for Pere Milà and his wife, Roser Segimón, who set up home in the first floor flat and rented out the four upper floors. To adapt it to the changing needs of a building with many tenants Gaudí made use of revolutionary building techniques. Using a structure of pillars and beams combined with a self-supporting non-load-bearing façade he achieved an interior where walls could be demolished and the layout changed at will. This masterly use of space is a direct precursor of the open-plan developments in nineteen-twenties rationalist architecture. Gaudí also laid out the flats in a functional manner around two large patios to ensure good lighting.
Beyond the structural innovations, however, what is most striking in the Casa Milà is the undulating stone façades with their surprising curved forms that recall the folds of a mountain or a cliff face. On completion, the work’s bold exterior was the subject of great controversy and attracted many negative comments, some of which maintained that the building looked like a quarry ("Pedrera"), a name which has stuck to it ever since. Other butts of popular humour were the original wrought iron railings that Gaudí designed for the balconies. Other unusual spaces in La Pedrera are the attic whose brick catenary arches recall the ribs of a whale, and the fantastic undulating roof terrace that incorporates organic-shaped skylights, ventilators and chimneys that constitute veritable sculptures.
Gaudí abandoned the works at the Casa Milà in 1910 after completing the basic structure due to disagreements with its developers, who rejected his proposal to crown the building with an immense sculpture of the Virgin. Pere Milà and Roser Segimón also objected to the architect's ideas for the interior decoration although these finally went forward, carried out over the years by collaborators of the architect. This entailed completion of the unusual plaster ceilings, the brilliant murals in the entranceway and the encaustic tiled floors with marine motifs designed by Gaudí himself.