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).
Manhattan
The skyscraper, which has shaped Manhattan's distinctive skyline, has been closely associated with New York City's identity since the end of the 19th century. From 1890 to 1973, the title of world's tallest building resided continually in Manhattan (with a gap between 1901 and 1908, when the title was held by Philadelphia City Hall), with nine different buildings holding the title. The New York World Building on Park Row, was the first to take the title in 1890, standing until 1955, when it was demolished to construct a new ramp to the Brooklyn Bridge. The nearby Park Row Building, with its 29 stories standing high took the title in 1899. The 41-story Singer Building, constructed in 1908 as the headquarters of the eponymous sewing machine manufacturer, stood high until 1967, when it became the tallest building ever demolished. The Metropolitan Life Insurance Company Tower, standing at the foot of Madison Avenue, wrested the title in 1909, with a tower reminiscent of St Mark's Campanile in Venice. The Woolworth Building, and its distinctive Gothic architecture, took the title in 1913, topping off at . Structures such as the Equitable Building of 1915, which rises vertically forty stories from the sidewalk, prompted the passage of the 1916 Zoning Resolution, requiring new buildings to withdraw progressively at a defined angle from the street as they rose, in order to preserve a view of the sky at street level.