The Tower, according to Guinness World Records:
What better honour is there than to be the first, the best, the highest or the fastest in the world at something?
It was 9:52 in the morning on March 31st, 1975, that the CN Tower officially became the World's Tallest Free-Standing Structure. This was according to Ross McWhirter, then the editor of the Guinness Book of World Records, who was on site to witness the placement of one of the last sections of antenna. Three days later, the last piece of antenna was attached bringing the overall height to 553.33 metres or 1815 feet, 5 inches.
The CN Tower held the record as the tallest building, tower, freestanding structure for over three decades. It remains the tallest in the Western Hemisphere. Guinness World Records over the years have included:
• World’s Tallest Free-standing Structure (1975)
• World’s Tallest Building and Free-standing Structure (1996)
• World’s Tallest Building (2003)
• World’s Tallest Tower (2007 – 2010)
Since then, the Tower has added the following distinctions:
-World's highest 'wine cellar' - 351 metres (1,151 ft.)
-On November 8, 2011 EdgeWalk at the CN Tower was presented with the Guinness World Record for the “Highest External Walk on a Building”.