In the 1920s the Des Moines area had several small airports for general aviation and airmail. In 1929, the Iowa General Assembly passed a law allowing cities to sell bonds and levy assessments to build municipal airports. Over 80 sites were considered for the Des Moines Airport until a decision was made to build on 160 acres (0.65 km²) of farmland south of the city. Construction of the airport began in 1932 and was completed in 1933. The airport's first passenger terminal was built shortly after the airport was completed. It was replaced by a new terminal in 1950 that has been expanded and renovated several times. The present concourses were built in 1970, along with the remodeling of the terminal. The airport itself has expanded several times from its original site and now covers 2,625 acres (10.6 km²).