CN Tower
"Guinness World Records" has called the CN Tower "the world's tallest self-supporting tower" and "the world's tallest free-standing tower". Although Guinness did list this description of the CN Tower under the heading "tallest building" at least once, it has also listed it under "tallest tower", omitting it from its list of "tallest buildings." In 1996, Guinness changed the tower's classification to "World's Tallest Building and Freestanding Structure". Emporis and the Council on Tall Buildings and Urban Habitat both listed the CN Tower as the world's tallest free-standing structure on land, and specifically state that the CN Tower is not a true building, thereby awarding the title of world's tallest building to Taipei 101, which is shorter than the CN Tower. The issue of what was tallest became moot when Burj Khalifa, then under construction, exceeded the height of the CN Tower in 2007 (see below).
List of tallest residential buildings
Since 2000, when CTBUH started maintaining a list of tallest residential skyscrapers The Belcher's Tower 1 and The Belcher's Tower 2 located in Hong Kong were the first tallest residential skyscrapers whose heights equal completed in 2000. In 2001, Trump World Tower in New York City became the tallest residential building in the world until it was surpassed in 2003 by the 21st Century Tower in Dubai. In 2012, Princess Tower in Dubai became the tallest residential building in the world before being surpassed by 432 Park Avenue in New York City in 2014. The percentage of residential buildings has been increased from 34 percent in 2009 to 45 percent in 2010 in residential skyscrapers whose height exceeds 200 metres, making Burj Khalifa the world's first megatall skyscraper to include residential space.