The document discusses Casa Mila, an apartment building in Barcelona, Spain designed by architect Antoni Gaudi and completed between 1905-1910. Some key features of Casa Mila include its wavy, undulating facade resembling waves or sand dunes; an organic, flowing style with no straight lines; and a dramatic roof with sculpted chimneys and forms. The document provides details on Gaudi's highly original and expressionistic design for Casa Mila, as well as images of its distinctive exterior and interior features.