CN Tower
"Guinness World Records" has called the CN Tower "the world's tallest self-supporting tower" and "the world's tallest free-standing tower". Although Guinness did list this description of the CN Tower under the heading "tallest building" at least once, it has also listed it under "tallest tower", omitting it from its list of "tallest buildings." In 1996, Guinness changed the tower's classification to "World's Tallest Building and Freestanding Structure". Emporis and the Council on Tall Buildings and Urban Habitat both listed the CN Tower as the world's tallest free-standing structure on land, and specifically state that the CN Tower is not a true building, thereby awarding the title of world's tallest building to Taipei 101, which is shorter than the CN Tower. The issue of what was tallest became moot when Burj Khalifa, then under construction, exceeded the height of the CN Tower in 2007 (see below).
JPMorgan Chase Tower (Houston)
The JPMorgan Chase Tower, formerly Texas Commerce Tower, is a , , 75-story skyscraper at 600 Travis Street in Downtown Houston, Texas, United States. It is currently the tallest building in the city, the tallest building in Texas, the tallest five-sided building in the world, the 19th-tallest building in the United States, and the 107th-tallest building in the world.