The industrialist Pere Milà and his wife Roser Segimon commissioned Antoni Gaudí to build an apartment house on the boundary separating Barcelona from the former town of Gràcia, with aim of turning the main floor into a family residence and leasing out the rest of the dwellings.

Antoni Gaudí built 2 blocks of flats, with separate entrances, arranged around 2 large interlinked patios, which facilitate the entry of light to all the dwellings, with a single undulating freestanding façade whose sinuous rhythms are echoed inside well. In addition, rather than the traditional weight-bearing walls, the building relies on a structure of pilars which allows for an open floor structure with large openings in the façade. The highly innovative construction and ornamental methods marked a departure from the traditional architectural design of the day.

The Casa Milà is popularly known as “La Pedrera” (the stone quarry) in allusion to the resemblance of its façade to an open quarry.