CN Tower
Construction on the CN Tower started on February 6, 1973 with massive excavations at the tower base for the foundation. By the time the foundation was complete, 56,000 tonnes (61,729 short tons) of dirt and shale were removed to a depth of 15 metres (49.2 ft) in the centre, and a base incorporating 7,000 cubic metres (9,156 cu yd) of concrete with 450 tonnes (496 short tons) of rebar and 36 tonnes (40 short tons) of steel cable had been built to a thickness of 6.7 metres (22 ft). This portion of the construction was fairly rapid, with only four months needed between the start and the foundation being ready for construction on top.
CN Tower
Construction on the CN Tower started on February 6, 1973 with massive excavations at the tower base for the foundation. By the time the foundation was complete, 56,000 tonnes (61,729 short tons) of dirt and shale were removed to a depth of 15 metres (49.2 ft) in the centre, and a base incorporating 7,000 cubic metres (9,156 cu yd) of concrete with 450 tonnes (496 short tons) of rebar and 36 tonnes (40 short tons) of steel cable had been built to a thickness of 6.7 metres (22 ft). This portion of the construction was fairly rapid, with only four months needed between the start and the foundation being ready for construction on top.