how long did it take to build the twin towers

The construction of the Twin Towers officially began in August 1968 for the North Tower, and January 1969 for the South Tower. The North Tower was topped out in December 1970, and the South Tower in July 1971. The Twin Towers were completed and officially dedicated on April 4, 1973. Thus, it took approximately 4.5 to 5 years to build the Twin Towers from the start of construction to completion and dedication, although tenants began moving in as early as December 1970 (North Tower) and January 1972 (South Tower) before full completion.