CN Tower

The CN Tower was conceived in the late 1960s as a solution to a specific technical problem: the growing interference between broadcast signals as Toronto's downtown skyline became denser and more complex. Multiple television and radio stations needed a single tall structure to transmit their signals clearly, and the tower was the answer. It opened on 12 April 1976 and became Toronto's defining landmark immediately.

At 553.3 metres, the CN Tower was upon completion the tallest free-standing structure on land in the world, and it held that record for thirty-two years — until the Burj Khalifa in Dubai surpassed it in 2008. The engineering challenge was to make the tower stable in the extreme wind conditions that Toronto's lakeside location can produce, and wind tunnel testing shaped every aspect of the tapered form that makes the tower visually distinctive.

The EdgeWalk, introduced in 2011, consists of a tether-secured walk around the main pod at 356 metres above ground, the hands-free experience taking approximately 30 minutes. It is one of the more unusual urban thrill experiences available anywhere, and the marketing has been effective — the EdgeWalk is now as synonymous with Toronto as the tower itself.

The LookOut level at 346 metres and the Glass Floor at 335 metres offer more measured perspectives. The Glass Floor — 25 millimetres thick — can support the weight of a large passenger vehicle, and standing on it and looking straight down through it at the city below is an experience that rewards the already dizzy with further vertigo.

The revolving restaurant at 351 metres, 360 The Restaurant, completes one full rotation per hour, giving diners a complete panoramic view of Toronto and Lake Ontario as the city shifts around them. It is a destination in its own right, not merely for the view — people come for the experience of dining while the city rotates past the windows.

The CN Tower sits at the centre of a dense cluster of Toronto's major entertainment, convention and transportation infrastructure — Union Station, the Rogers Centre, the Air Canada Centre — that has developed around it since the tower's construction. The tower is the reference point from which all other distances in the city are measured.

The tower's nighttime illumination has been programmed for civic occasions, sporting events and cultural celebrations since 2007, under an agreement that replaced the earlier static lighting with a dynamic system capable of displaying specific colours and sequences for designated events.

The tallest structure in the Western Hemisphere for over four decades, it redefined what a communications tower could be and became the defining symbol of Toronto and, by extension, modern Canada.

The combination of observation decks, revolving restaurant and the EdgeWalk thrill experience makes it one of the most complete high-altitude attraction complexes in the world.

Declared one of the modern Seven Wonders of the World by the American Society of Civil Engineers in 1995, placing it in the company of the Panama Canal and the Empire State Building.