The CN Tower is a communications and observation tower in Toronto, Ontario, Canada. Standing 553.3 metres (1,815 ft) tall, it was completed in 1976, becoming the world's tallest free-standing structure and world's tallest tower. It held both records for 34 years, or one-third century, until the completion of the Burj Khalifa in Dubai and Canton Tower in Guangzhou. It remains the tallest free-standing structure in the Western Hemisphere, a signature icon of Toronto's skyline, and a symbol of Canada, attracting more than two million international visitors annually.

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, where it holds second-place ranking.