Casa Milà, better known as La Pedrera (Catalan for 'The Quarry'), is a building designed by the Catalan architect Antoni Gaudí and built in the years 1905-1907. It is located at 92, Passeig de Gràcia ('passeig' is Catalan for promenade or avenue) in the Eixample district of Barcelona. It was built for Roger Segimon de Milà. It is part of the UNESCO World Heritage Site "Works of Antoni Gaudí".

Most people consider it magnificent and overwhelming; some say it is like waves of lava or a sand-dune. This building seems to break our understanding of conventional architecture. The most astonishing part is the roof with an almost lunar appearance and dreamlike landscape.

The building can be considered more of a sculpture than a regular building. Critics remark on its detachment from usefulness, but others consider it to be art. The Barcelonese of the time considered it ugly, hence the "quarry" nickname, but today it is a landmark of Barcelona.

It could be compared with the steep cliff walls in which African tribes build their cave-like dwellings. The wavy facade, with its large pores, reminds one also of an undulating beach of fine sand, formed, for example, by a receding dune. The honeycombs made by industrious bees might also spring to the mind of the observer viewing the snake-like ups-and-downs that run through the whole building.

Casa Milà was a predecessor of some buildings with a similar biomorphic appearance:

a) the 1921 Einstein Tower in Potsdam, designed by Erich Mendelsohn

b) Solomon R. Guggenheim Museum in New York, designed by Frank Lloyd Wright

c) Chapelle Notre Dame du Haut, Ronchamp, France, designed by Le Corbusier

d) the Hundertwasserhaus and other works by Austrian architect Friedensreich Hundertwasser

e) Disney Concert Hall in Los Angeles, by Frank Gehry

Free exhibitions are often held on the first floor, which also provides some opportunity to see the interior design. There is a charge for entrance to the apartments and roof.