Aalto's work was distinguished by a remarkable sensitivity to natural materials, especially to timber which featured prominently in his Finnish Pavilions at the Paris Exhibition (1937) and the New York World Fair (1939). He showed an almost instinctive approach to the creation of forms, which prevented his work from lapsing into any of the architectural clichés of his day. And he was able to integrate his architecture with landscape and with local building tradition.
After the Second World War, Aalto began building in red brick and timber. A fine example from this so-called “red” period is the Civic Center at Säynätsalo (1950 - 2). In the early 1950s, his work upon the redesigning of Helsinki began in earnest. Projects included the Otaniemi Polytechnic (begun 1955), and the Cultural Center (1955 - 8). The main building of the Institute of Technology in Otaniemi (executed 1961 - 4) and Finlandia house in Helsinki are among of his last major works.
Further reading Quantrill, M.
Alvar Aalto: A Critical Study, New York (1983).