The CVU ranks the
height of buildings using three different methods: •
Height to architectural top: This is the main criterion under which the CVU ranks the height of buildings. Heights are measured from the level of the lowest, significant, open-air, pedestrian entrance to the top of the building, inclusive of spires but excluding items such as flagpoles and antennae. •
Highest occupied floor: Height to the floor level of the highest floor that is occupied by residents, workers or other building users on a consistent basis. •
Height to tip: Height to the highest point of the building, including antennae, flagpoles, and technical equipment. A category measuring to the top of the roof was removed from the ranking criteria in November 2009. This is because flat-topped skyscrapers are not as common in the modern era, as skyscrapers with intricate spire designs and parapet features atop their roofs make it more difficult to define the roof of a building. The CVU insist that a building should only be added to the official tallest list when it is (i) topped out structurally and architecturally, (ii) fully clad, and (iii) open for business, or at least partially open. This became the CVU official definition of a building's "completion". The CTBUH maintains an extensive database (named The Skyscraper Center) of the tallest buildings in the world, organized by various categories. Buildings under construction are also included, although not ranked until completion. The CTBUH also produces an annual list of the 10 tallest buildings completed in that particular year. ==Events==