The Calgary Tower is a 190.8-metre (626 ft) free-standing observation tower in the downtown core of Calgary, Alberta, Canada. Originally called the Husky Tower, it was conceived as a joint venture between Marathon Realty Company Limited and Husky Oil as part of an urban renewal plan and to celebrate Canada's centennial of 1967. The tower was built at a cost of CA$3,500,000 and weighs approximately 10,884 tonnes, of which 60% is below ground. It opened to the public on June 30, 1968, as the tallest structure in Calgary and the tallest in Canada outside Toronto. It was renamed the Calgary Tower in 1971.