"The AT&T Michigan Headquarters is a complex of skyscrapers and buildings located at 1st Street, Cass Avenue, State Street, and Michigan Avenue in Downtown Detroit, Michigan. It contains the AT&T Building, the AT&T Building addition, the Maintenance Shop and is owned by communications giant AT&T."@en . . "1719"^^ . . "AT&T Michigan Headquarters"@en . . "1917" . "1919, 1928, 1973" . .