CN TOWER

The CN Tower is a major tourist destination, with over 2 million visitors a year. It also broadcasts over 30 Toronto television and FM radio signals across Southern Ontario in addition to wireless paging and cellular telephone signals. Various features have been added since opening. The very brave can test their courage by walking across the glass floor. Others travel higher up the tower to the Sky Pod, another 33 stories above ground.

Tower Rises Above the Sky

By the late 1960s, the City of Toronto desperately needed a new transmission antenna because new skyscrapers were blocking out aerial reception for televisions. The CN tower was planned as both a telecommunications tower and a tourist attraction. The original project included “Metro Centre”, a complex with entertainment and sports venues but this would have included the demolition of Union Station. Although the larger project was stopped, the head of CN at the time proceeded with the tower as it is today on CN’s rail yards. 15 years later, the idea of building a sports venue was accomplished when the SkyDome (Rogers Centre) was opened in 1989.

Construction Drama

Once the main tower was completed, the final steps in February 1974 before the grand opening were truly dramatic. First, the giant crane used during construction had to be removed, and then a 102-metre steel broadcasting antenna had to be added to the top. Project managers called upon Olg – a 10-ton Sikorsky helicopter. Once the crane was gone, it took another 3½ weeks until all the pieces of the antenna were carefully put in place. When the final piece was hammered in by ironworker Paul Mitchell on April 2, 1975, he danced a jig 1,815 feet above the earth to celebrate!

As published in the National Post on Celebrating CN Tower’s 30th Birthday, “Waving to a crowd of thousands below, and with a storm approaching, neither Mr. Mitchell nor the tower’s architect, Ned Baldwin, imagined their masterpiece would reign for three decades as the world’s tallest building.”

Built to Last

The tower is built to last – experts say 300 years or more. The strength of wind that could blow it over doesn’t exist, so it’s going to remain a distinct part of our skyline for a long time!

The base of the tower sits on bedrock over 12 metres below ground. But the real secret is inside the structure. According to one of its architects, Ned Baldwin, metal anchors secure post tension steel cables inside the concrete. The cables run through steel ducts in the tower’s hexagonal concrete core as well as in ducts in the wings. At the base of the foundation the cables are pulled tight. On a windy day, the tower actually moves in an eclipse pattern, somewhere between 1 and 4 meters.

Above all, the CN Tower is still the dominant feature of Toronto’s skyline, our most defining landmark, stretching over half a kilometre into the sky.

SkyDome

Alongside the CN Tower is SkyDome. Although they were developed at different times, the two structures feel inseparable.

When it opened, SkyDome was the world’s first stadium with a retractable roof and currently home to the Toronto Blue Jays and Toronto Argonauts. With Blue Jay fever hitting Toronto this fall, many still do believe that one of the SkyDome’s finest moments was Joe Carter’s World Series winning home run on October 23, 1993.

In the mid-1980s, architects and engineers were invited to submit proposals in the “Ontario Stadium Project” for the design and location of a multiuse sports facility. The winning entry from structural engineers Bill Allen and Rod Robbie proposed a circular stadium with a retractable roof at the base of the CN Tower.

At full capacity, the dome seats 65,000 but it can be adapted for concerts, football, baseball, and before the Air Canada Centre opened, basketball. The roof has always been one of its more fascinating design elements. Made up of 4 sections, which open in a smooth, circular motion, the north panel always remains stationary. Covering 7 acres, it opens or closes in just 20 minutes.

Over the years, the building has changed ownership, most recently purchased by Rogers Communications, owners of the Blue Jays.