The name “CN” originally referred to Canadian National, the railway company that built the tower. Following the railway’s decision to divest non-core freight railway assets, prior to the company’s privatization in 1995, it transferred the tower to the Canada Lands Company, a federal Crown corporation responsible for real estate development.
The idea of the CN Tower originated in 1968 when the Canadian National Railway wanted to build a large TV and radio communication platform to serve the Toronto area, as well as demonstrate the strength of Canadian industry and CN in particular.
These plans evolved over the next few years, and the project became official in 1972. Built on the former Railway Lands, it was completed in 1976, becoming the world’s tallest free-standing structure and world’s tallest tower at the time. It held both records for 34 years until the completion of Burj Khalifa and Canton Tower in 2010.
After months and hard work of construction, the CN Tower was opened to the public on June 26, 1976 and it was well on its way to becoming the country’s most celebrated landmark.
It is the centre of telecommunications for Toronto serving over 16 Canadian television and FM radio stations, the workplace of over 500 people throughout the year, and an internationally renowned tourism destination.
The CN Tower was built by Canadian National who wanted to demonstrate the strength of Canadian industry by building a tower taller than any other in the world. Building the CN Tower was a vast and ambitious project that involved 1,537 workers who worked 24 hours a day, five days a week for 40 months to completion.
The original plan for the tower envisioned a tripod consisting of three independent cylindrical “pillars” linked at various heights by structural bridges. Had it been built, this design would have been considerably shorter, with the metal antenna located roughly where the concrete section between the main level and the SkyPod lies today.
As the design effort continued, it evolved into the current design with a single continuous hexagonal core to the SkyPod, with three support legs blended into the hexagon below the main level, forming a large Y-shape structure at the ground level.
To build the main support pillar, a hydraulically raised slipform was built at the base. This was a fairly impressive engineering feat on its own, consisting of a large metal platform that raised itself on jacks at about 6 m (19.7 ft) per day as the concrete below set.
Concrete was poured continuously by a team of 1,532 people until February 22, 1974, during which it had already become the tallest structure in Canada, surpassing the recently built Inco Superstack, which was built using similar methods. In total, the tower contains 40,500 m3 (52,972 cu yd) of concrete, all of which was mixed on-site in order to ensure batch consistency.
For over three decades, the CN Tower continues to remain a critical telecommunications link adapting over the years to the incredible advances of the last decades by providing a cell site for wireless voice and data transmissions as well as for radio and television broadcasts.