
The assessment of the height of artificial structures has been controversial. There are dozens of radio and television broadcasting towers which measure over 600 metres (about 2,000 ft) in height, and only the tallest are recorded in publicly available information sources. Structures that do not meet this criterion, such as the CN Tower, are defined as " towers". The Council on Tall Buildings and Urban Habitat, an organization that certifies buildings as the "World's Tallest", recognizes a building only if at least 49% of its height is made up of floor plates containing habitable floor area. The tallest guyed structure is the KVLY-TV mast at 606 metres (1,987 ft). The second-tallest self-supporting structure and the tallest tower in the world is the Tokyo Skytree. The building gained the official title of " tallest building in the world" and the tallest self-supported structure at its opening on January 9, 2010. The world's tallest human-made structure is the 828-metre-tall (2,717 ft) Burj Khalifa in Dubai, United Arab Emirates.

The Burj Khalifa in Dubai, United Arab Emirates
