Vanity height is defined by the Council on Tall Buildings and Urban Habitat as the height difference between a skyscraper's pinnacle and the highest usable floor (usually observatory, office, restaurant, retail or hotel/residential). Because the CTBUH ranks the world's tallest buildings by height to pinnacle, a number of buildings appear higher in the rankings than they otherwise would due to extremely long spires. When vanity height is excluded, the height progression of the world's tallest buildings looks much more modest in comparison.