Input (grade 9): The tallest is the Burj Khalifa skyscraper at 828 m, but most of the structures listed are television broadcasting masts, followed by a mix of the taller tower-type structures (e.g. the CN Tower) and the taller high-rise buildings (like Willis Tower).
Output (grade 7): Most of the structures are television broadcasting masts. There are also the taller tower-type structures (like the CN Tower) and the taller high rise buildings (like the Sears Tower).