The Casa Milà is one of Antoni Gaudí's most unique works. Situated right on the Passeig de Gràcia in Barcelona, it breaks with the physiognomy of the avenue. It is a building constructed with two interior patios and a basement, lower floor, main floor, four apartments, attic and roof. Gaudí established the building's structure based on stone pillars, brick and iron and the main support of the catenary archand parabolic arch.

Its construction generated a great deal of controversy in the early 1900's. Barcelonans gave it the nickname "La Pedrera," (the quarry) which refers to the type of creamy white stone used that comes from the quarries in Garraf and Vilafranca del Penedès.

Many also described it as a large boat that rowed along the Passeig de Gràcia. The building's façade is characterised by theundulations and openings in the stone to facilitate interior lighting and ventilation.

The building featured 20 homes that were rented to affluent families of the era. The Milà couple, the owners of the property, lived in the penthouse apartment. La Pedrera, however, is not a conventional residential building. Gaudí's objective was to create dwellings in movement, where everyone could have their own layout according to the needs of each tenant

The building is crowned with a rooftop terrace, finished with seven chimneys, covered withlime, white 'trencadís' (mosaic) and glass. The heads of seven mythological warriors are featured, which, from the almost imaginary rooftop, watch over the city.