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).
Architecture of New York City
New York City has a long history of tall buildings. It has been home to 10 buildings that have held the world's tallest fully habitable building title at some point in history, although half have since been demolished. The first building to bring the world's tallest title to New York was the New York World Building, in 1890. Later, New York City was home to the world's tallest building for 75 continuous years, starting with the Park Row Building in 1899 and ending with 1 World Trade Center upon completion of the Sears Tower in 1974. The 1899 Park Row Building, one of the world's earliest skyscrapers, is still standing.