We take a look at the world's tallest buildings, taking into account a building's roof height or spire height. We did not include the building's antenna height. Using this method, the Petronas Towers appear taller than Chicago's Willis Tower, which in-fact has more floors than the Petronas Towers. 

According to Skycraperspage.com, we have listed the five building from tallest to shortest.

1.) Burj Khalifa

2.) Taipei 101

3.) Shanghai World Financial Center

4.) International Commerce Center (Hong Kong)

5.) the Petronas Towers.  

By 2010 it is predicted that the Burj Khalifa will still be the tallest building in the world with 168 floors and a spire of 828m. Following it will be the Pingan International Finance Center and the Shanghai Tower, both located in China.

After the Shanghai Tower, the Makkah Royal Clock Tower Hotel in Mecca, Saudi Arabia, is slated to be the fourth tallest with a spire of 601m. And in 2015, New York City will stand tall and proud with its new One World Trade Center building, consisting of 105 floors with a spire of 541.3m, making it the 5th tallest building in the world. 

Despite the current economic downturn, the world of architecture won't be slowing down in 2015. The India Tower in Mumbai is slated to be the world's tallest building in 2016 according to Infrastructurist.com

To see a slideshow of the world's tallest buildings now under construction, click here