While determining the world's tallest structure has generally been straightforward, the definition of the world's tallest building or the world's tallest tower is less clear. The disputes generally centre on what should be counted as a building or a tower, and what is being measured.

In terms of absolute height, the tallest structure is currently the Burj Dubai, although it will not hold the official title of "Tallest Building in the World" until the building is officially opened. The current official holder of the "Tallest Building in the World" is held by Taipei 101. In addition, there are dozens of radio and television broadcasting towers which measure over 600 metres (about 2,000 feet) in height. There is, however, some debate about:

whether structures under construction should be included in the list
whether structures rising out of water should have their below-water height included.
For towers, there is a debate over:

whether guy-wire-supported structures should be counted
For buildings, there is debate over:

whether communication towers with observation galleries should be considered habitable buildings.
whether only habitable height is considered.
whether roof-top antennas should be considered towards height of buildings; with particular interest in whether components that look like spires can be either classified as antennas or architectural detail.
The Council on Tall Buildings and Urban Habitat, the organization that determines the title of the "World’s Tallest Building," recognizes a building only if at least fifty percent of its height is made up of floor plates containing habitable floor area. Structures that do not meet this criterion, such as the CN Tower, are defined as "towers."


source:http://en.wikipedia.org/wiki/List_of_tallest_buildings_and_structures_in_the_world


In my opinion, the world's buildings are getting taller and taller, and it is never enough, continuous all the time. It is all about ego. Once the country has the building, it shows power. It was common phenomena in 1970s era in United State of America, the rapid growth of building was unstopable. In 1998 Malaysia has Petronas Twin Towers, the building that Malaysian can be proud of. Combining elements in its desgin, it shows harmony and the building is rooted in tradition and about Malaysia's aspiration and ambition. Instantly at that particular time, the world realize instantly about Malaysia and its characteristics.