The CN Tower is a 553.33 m high (1,815.4 ft) concrete communications and observation tower in downtown Toronto, Ontario. Upon completion in 1976, it was the world's tallest free-standing structure and tallest tower. It held both records for 34 years until the completion of Burj Khalifa and Canton Tower, respectively, both in 2010. It remains the tallest free-standing structure in the Western Hemisphere.Photograph: Taxiarchos228