This measurement only recently came into use, when the Petronas Towers passed the Sears Tower (now named Willis Tower) in height. The former was considered taller because its spires were considered architectural, while the latter's antennae were not. This led to the split of definitions, with the Sears Tower claiming the lead in this and the height-to-roof (now highest occupied floor) categories, and with the Petronas claiming the lead in the architectural height category.