The idea of the CN Tower originated from the 1968 Canadian National Railway's desire to build a large TV and radio communication platform to serve the Toronto area, as well as demonstrate the strength of Canada and Canadian industry.
It surpassed the height of the Ostankino Tower while still under construction in 1975, becoming the tallest free-standing structure on land in the world for the next 31 years. It also contains a metal staircase with 2,579 steps leading to the top of the tower. It is the tallest metal staircase on Earth.
The CN Tower's claim as the world's tallest tower, was surpassed on September 12, 2007 by the Burj Khalifa (formerly known as Burj Dubai. It has since also been surpassed by the Guangzhou TV & Sightseeing Tower in 2009.
Between 2010 and 2013, the rank of the CN Tower in the list of the world tallest structures is expected to drop considerably. At least seven structures currently under construction, all of which are scheduled to be completed by 2013, are expected to exceed the CN Tower's height of 553.33 metres once completed.
Despite this, the CN tower remains the tallest free-standing structure in the Western Hemisphere, the signature icon of Toronto's skyline, and a symbol of Canada. It can also hold onto at least one claim to fame, that of the tallest metal staircase on the planet, something which none of the other buildings (whose staircases may be taller but are not metal) can claim