The base floor plan of Casa Mila encompasses a total area of more than 100 sqare metres. It includes two enormous circular patios, providing virtually every part of the house with natural sunlight. Constructed entirely of natural stone, it completely lacks artificial colouring and decoration, an expression of Gaudi's Romantic and anti-Classical approach to design. It was commissioned as a residence for the Mila family and erected in the period 1906-10; however, at the time of its inauguration, neither the original commissioners nor the general public liked Gaudi's creation. It was at that time that it was mockingly nicknamed La Pedrera (Stone Quarry). It took several decades for it to gain international acclaim; in 1984, it became a UNESCO World Heritage Site.

Probably one of the most interesting aspects of Casa Mila is its elaborate rooftop, featuring a curious gathering of Surrealist chimneys of various, sculpture-like forms. A famous scene from Michelangelo Antonioni's 'Professione: Reporter' was filmed in this peculiar surrounding. The innovative biomorphic appearance of La Pedrera gave rise to a new trend in architecture, reflected in the design of such famous landmarks as the Einstein Tower in Potsdam, works of Friedensreich Hundertwasser, Chapelle Notre Dame du Haut in Ronchamp, France, and the Guggenheim Museum in New York City.