On June 26, 2001 the CN Tower, the World's Tallest Building and Free Standing Structure will celebrate its 25th Anniversary. Defining the Toronto skyline, the CN Tower is Canada's most recognizable and celebrated icon, an important telecommunications hub, and the
center of tourism in Toronto.
At a height of 1,815 feet or 553 metres, the CN Tower has maintained its designation as the World's Tallest Building and Free Standing Structure for a record 25 years. A feat that has not gone unnoticed. The CN Tower was built in 1976 by Canadian National (CN) who wanted to demonstrate the strength of Canadian industry by building a tower taller than any other in the world.
CN Tower construction crews moved in on February 6, 1973, and started to remove over 56 metric tonnes of earth and shale for the foundation. Once the foundation was ready, work began on the CN Towers 335 m (1,100ft.) concrete shaft, a hexagonal core with three curved support arms. This involved pouring concrete into a massive mold or "slipform". As the concrete hardened, the slipform, supported by a ring of climbing jacks powered by hydraulic pressure, moved upwards, gradually decreasing in size to produce the CN Towers gracefully tapered contour.
Eight months later, the CN Towers concrete shaft was the tallest structure in Toronto and by February 1974, it was the tallest in Canada. In August 1974, work began on the seven-story tower sphere that would eventually house the observation decks and revolving restaurant. The CN Tower approached completion in March 1975, when Olga, the giant Russian Sikorsky helicopter flew into the city to lift the 44 pieces of the antenna into place.
On April 2, 1975 when the OLGA helicopter lifted the 44th and final piece of the CN Tower's antenna into place, the CN Tower joined the ranks of 17 other great structures that had previously held the title of World's Tallest Free-Standing Structure. Ross McWhirter, editor of the Guinness Book of World Records, was on hand to record the milestone for history and since then, the CN Tower has received numerous mentions in the famous book including the Worlds Longest Metal Staircase and most recently, the Worlds Highest Wine Cellar. In 1996, the CN Towers classification was officially changed to the Worlds Tallest Building and Free-Standing
The cost then to build the CN Tower was $63 million, approximately $300 million today. It was an ambitious project that involved 1,567 workers who worked 24 hours a day, five days a week for 40 months to completion. Key project team members were NCK Engineering as structural engineer; John Andrews Architects; Webb, Zerafa, Menkes, Housden Architects; Foundation Building Construction and Canron (Eastern Structural Division).
After 40 months of construction, the CN Tower was finished on April 2, 1975 and opened to the public on June 26, 1976. Although less than one year old, it was well on its way to becoming the countrys most celebrated landmark. Twenty-five years later, it is the
center of telecommunications for Toronto serving 16 Canadian television and FM radio stations, the workplace of up to 550 people throughout the year, and one of Torontos premier entertainment destinations.
In 1995, the CN Tower was classified as one of the Seven Wonders of the Modern World by the American Society of Civil Engineers. The Worlds Tallest Building shares this designation with the Itaipu Dam on the Brazil/Paraguay border, the Golden Gate Bridge in San Francisco, the Panama Canal, the Chunnel under the English Channel, the North Sea Protection Works off the European coast, and the Empire State Building.
Since the CN Tower opened, Canadians and tourists from around the world have made the trip to Toronto to celebrate this marvel of civil engineering. Besides serving as a telecommunications hub, the CN Tower provides world-class entertainment and a wide range of unique attractions, exhibits and food and beverage venues.
In past years, the CN Tower has supported its vision of Torontos premier entertainment destination by totally renovating and redesigning 360 Restaurant, building the Worlds Highest Wine Cellar, and adding two new elevators.
On June 26, 1997, TrizecHahn Corporation, one of North Americas largest real estate companies signed a long-term operating and management lease for the CN Tower and its adjoining base lands. Under the management of TrizecHahn, the landmark underwent the most significant change in its 25-year history. A $26 million entertainment expansion and revitalization.
This article was published in http://www.cntower.ca/ site. For those who don't know what CN Tower is.. this tower featured in recent Telugu films Narasimha Naidu and Chirunavvutho in the songs.