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History & Construction of CN Tower: Architecture Defines Toronto

Article by Brotee Das Datta / Additional writing and research by Mike Simpson

Defining the Toronto skyline at 553.33m, the CN Tower is undoubtedly the most recognizable structure of the city. This iconic Canadian structure is visited by over two million international tourists every year. Even 44 years after being constructed, the CN Tower is deeply admired and celebrated by Canadians.

As a proud Torontonian, I find the history and construction details of the CN Tower quite intriguing. Many of us do not know the story behind this iconic structure and how it is closely associated with the history of Toronto. This iconic project was originally initiated by the Canadian National Railways and the official design of the structure started in 1972. Constructed on former railway lands, the ambitious construction project was led by Canada Cement Company. The CN Tower represents the rapid growth and urbanization of Toronto during the late 1960s to early 1970s. In 1973, the construction was officially started with excavating the base of the structure. 

The CN Tower is visible all over the city, particularly the waterfront / Photo by Tdot Mike @tdot_mike

Why build so high? According to the CN Tower website, the 1960s brought a boom in the construction of high-rise buildings and skyscrapers: 

“These buildings caused serious communications problems for existing transmission towers, which were simply not high enough to broadcast over the new buildings. Signals bounced off the buildings creating poor television and radio reception for residents. With its microwave receptors at 338 m (1,109 ft.) and at the 553.33m (1,815 ft., 5 inches) antenna, the CN Tower swiftly solved the communications problems with room to spare and as a result, people living in the Toronto area now enjoy some of the clearest reception in North America. 

Breaking the world height record and establishing Toronto’s tower as the tallest was also a consideration. Eventually the design would erase the record held by Moscow’s Ostankino tower.

According to an article in the Urban Toronto website:

“There was also the question of just how high the tower should go, coupled with the very real possibility that a world record could be broken. President and CEO of Canadian National Robert Bandeen, described by Quinn as a “visionary with artistic sense”, pushed for a height surpassing that of the Ostankino Tower. His wish would be granted — the tower’s final height measured 553.3 metres, trumping Moscow’s landmark by 13 metres. 

As a civil engineer, I personally find the design and construction methodology of the CN Tower quite fascinating. The structural designers were well aware that this was going to be one of the tallest structures in the world and took the appropriate design measures to ensure the safety of the structure. The construction took place in several phases. Several design modifications took place during construction to maintain the structural integrity of the structure. The CN Tower construction project involved over 1,500 workers who worked in shifts, 24 hours a day, five days a week for 40 months to complete the structure. The project cost CAD $63 million and the completed structure was opened to the public in June 1976.

The CN Tower held the record of the tallest free-standing structure in the world for 32 years until the Burj Khalifa (Dubai, U.A.E.) surpassed it in 2007. Currently, the CN Tower is the fifth highest observation deck in the world which includes several observation decks and a revolving restaurant on top of the tower. Even today, the Toronto skyline is unquestionably unimaginable without this iconic structure.  For anyone visiting Toronto, this iconic structure is a definite must-visit.

Sitting on top of Toronto. Perched 1,100 feet above Toronto and 27 feet out from the growing CN Tower; iron worker Larry Porter pulls at the hook of a giant crane as he installs outriggers that will be used to support the restaurant. He gets $8.01 hourly; below 1;000 feet; $1 more above that level as danger pay. 

Photo credits: these photos were sourced from the Toronto Star Archives via the Toronto Public Library – thanks to the photographers Boris Spremo and Doug Griffin.

Links and Resources

Video – How the CN Tower was Built – https://youtu.be/K67j5juf-V4

CN Tower website – Article on tower history

Urban Toronto – Article on origin of tower

CBC Article – Before the glass floor and EdgeWalk

About the Authors

Brotee Das Datta is a writer based in Toronto, and the creator of Stories of TO – check it out on Instagram @storiesofto

Mike Simpson is the editor and curator of Tdot Shots. He’s a designiroer and educator from Toronto. He leads Toronto tours and photo walks focused on art and architecture.

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