What is the casa mila made of?

The Casa Mila apartment house was a late example of Antonio Gaudi 's apartment house was a late example of Antonio Gaudi 's commercial design. On a corner site, the building facade is curvilinear in form and based on organic concepts. The heavy facade is tied to the floors behind. The most successful portions of the design were the roof vaults, clustered chimneys, and balcony railings designed by Jujol. This design caused much public comment, and Antonio Gaudi was forced to defend his organic forms in general terms.