where did the steel to make tokyo tower come from
Tokyo Tower The new construction project attracted hundreds of tobi (鳶), traditional Japanese construction workers who specialized in the construction of high-rise structures. The Takenaka Corporation broke ground in June 1957 and each day at least 400 laborers worked on the tower.[5] It was constructed of steel, a third of which was scrap metal taken from US tanks damaged in the Korean War.[9][10] When the 90-metre antenna was bolted into place on 14 October 1958, Tokyo Tower was the tallest freestanding tower in the world, taking the title from the Eiffel Tower by 13 metres.[5] Despite being taller than the Eiffel Tower, Tokyo Tower only weighs about 4,000 tons, 3,300 tons less than the Eiffel Tower.[11] While other towers have since surpassed Tokyo Tower's height, the structure was still the tallest artificial structure in Japan until April 2010, when the new Tokyo Skytree became the tallest structure in Japan.[8] It was opened to the public on 23 December 1958 at a final cost of ¥2.8 billion ($8.4 million in 1958).[10][12] Tokyo Tower was mortgaged for ¥10 billion in 2000.[13]
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.