when did the construction of the world trade center begin
Construction of the World Trade Center Construction of the World Trade Center's North Tower began in August 1968, and the South Tower in 1969. Extensive use of prefabricated components helped to speed up the construction process. The first tenants moved into the North Tower in December 1970 and into the South Tower in January 1972. Four other low-level buildings were constructed as part of the World Trade Center in the early 1970s, and the complex was mostly complete by 1973. A seventh building, 7 World Trade Center, was opened in 1987.
World Trade Center (1973–2001) The original World Trade Center was a large complex of seven buildings in Lower Manhattan, New York City, United States. It featured the landmark twin towers, which opened on April 4, 1973, and were destroyed as a result of the September 11 attacks in 2001. At the time of their completion, the "Twin Towers"—the original 1 World Trade Center, at 1,368 feet (417 m); and 2 World Trade Center, at 1,362 feet (415.1 m)—were the tallest buildings in the world. The other buildings in the complex included the Marriott World Trade Center (3 WTC), 4 WTC, 5 WTC, 6 WTC, and 7 WTC. All these buildings were built between 1975 and 1985, with a construction cost of $400 million ($2,300,000,000 in 2014 dollars).[4] The complex was located in New York City's Financial District and contained 13,400,000 square feet (1,240,000 m2) of office space.[5][6]