The CN Tower (French: Tour CN) is a 553.3 m-high concrete communications and observation tower in downtown Toronto, Ontario, Canada.
Built on the former Railway Lands, it was completed in 1976. Its name “CN” 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 CN Tower held the record for the world’s tallest free-standing structure for 32 years, from 1975 until 2007, when it was surpassed by the Burj Khalifa, and was the world’s tallest tower until 2009 when it was surpassed by the Canton Tower. It is currently the ninth-tallest free-standing structure in the world and remains the tallest free-standing structure on land in the Western Hemisphere. In 1995, the CN Tower was declared one of the modern Seven Wonders of the World by the American Society of Civil Engineers. It also belongs to the World Federation of Great Towers.
The CN Tower consists of several substructures. The main portion of the tower is a hollow concrete hexagonal pillar containing the stairwells and power and plumbing connections. The tower’s six elevators are located in the three inverted angles created by the Tower’s hexagonal shape (two elevators per angle). Each of the three elevator shafts is lined with glass, allowing for views of the city as the glass-windowed elevators make their way through the tower. The stairwell was originally located in one of these angles (the one facing north), but was moved into the central hollow of the tower; the tower’s new fifth and sixth elevators were placed in the hexagonal angle that once contained the stairwell. On top of the main concrete portion of the tower is a 102-meter-tall metal broadcast antenna, carrying television and radio signals.
There are three visitor areas: the Glass Floor and Outdoor Observation Terrace, which are both located at an elevation of 342 meters, the Indoor Lookout Level located at 346 meters, and the higher SkyPod at 446.5 meters, just below the metal antenna. The main deck level has seven storeys, some of which are open to the public.
A metal staircase reaches the main deck level after 1,776 steps, and the SkyPod 100 m above after 2,579 steps; it is the tallest metal staircase on Earth. These stairs are intended for emergency use only and are not open to the public, except for charity stair-climb events two times during the year. The average climber takes approximately 30 minutes to climb to the base of the radome. The tower changes its lighting scheme on holidays and to commemorate major events.
The CN Tower held the record for the world’s tallest free-standing structure for 32 years, from 1975 until 2007, when it was surpassed by the Burj Khalifa, and was the world’s tallest tower until 2009 when it was surpassed by the Canton Tower. It is currently the ninth-tallest free-standing structure in the world and remains the tallest free-standing structure on land in the Western Hemisphere. In 1995, the CN Tower was declared one of the modern Seven Wonders of the World by the American Society of Civil Engineers. It also belongs to the World Federation of Great Towers.
According to Wikipedia
