History of Chicago upper income Americans continued to move from the city for better housing and schools in the suburbs. Office building resumed in the 1960s. When completed in 1974, the Sears Tower, now known as the Willis Tower, at 1451 feet was the world's tallest building. It was designed by the famous Chicago firm of Skidmore, Owings & Merrill, which designed many of the city's famous buildings. Mayor Richard J. Daley served 1955–1976, dominating the city's machine politics by his control of the Cook County Democratic Central Committee, which selected party nominees, who were usually elected in the Democratic stronghold. Daley took
Willis Tower unfinished World Trade Center to become the world's tallest building. The height was restricted by a limit imposed by the Federal Aviation Administration (FAA) to protect air traffic. The financing of the tower was provided by the Sears company. It was topped with two antennas to permit local television and radio broadcasts. Sears and the City of Chicago approved the design, and the first steel was put in place in April 1971. The structure was completed in May 1973. The construction cost about US$150 million at the time, equivalent to $ million in 2019. By comparison, Taipei 101, built in