Q. What is the World's Tallest Building?
A.
It depends on who does the measuring! Skyscraper buffs disagree on whether features like flagpoles, antennas, and spires should be included when measuring building height.
Also under dispute is the question of what, exactly, constitutes a building. Technically, observation towers and communications towers are considered structures, not buildings, because they are not habitable. They do not have residential or office space.
If you count only habitable space and measure from the sidewalk level of the main entrance to the structural top of building (excluding flagpoles and spires), then the tallest buildings in the world are the Petronas Twin Towers in Kuala Lumpur, Malaysia. Designed by Cesar Pelli and completed in 1998, the Petronas Twin Towers are approximately 452 meters (1,483 feet) tall.
If you include decorative spires, then the almost-completed Taipei 101 Tower in Taipei, Taiwan is the world's tallest building. With the soaring spike on its roof, Taipei Tower is about 508 meters (1,667 feet) tall. But Taipei Tower will not keep its ranking for long. When it is completed, the new World Trade Center in New York City is expected to rise 541 meters (1,776 feet) tall, including its enormous spire.
However, if spires, flagpoles, and antennas can be counted when we measure building heights, perhaps rankings of the World's Tallest Buildings should include all man-made structures, whether or not they contain habitable space. In this case, the CN Tower in Canada is the world's tallest building. The communications tower and tourist attraction measures 553.33 meters (1,815 ft., 5 inches) tall.