The Petronas Towers (also known as the Petronas Twin Towers or KLCC) are skyscrapers and twin towers in Kuala Lumpur, Malaysia. They were the tallest buildings in the world from 1998 to 2004 until surpassed by Taipei 101, but remain the tallest twin buildings in the world.The building is the landmark of Kuala Lumpur with nearby Kuala Lumpur Tower.

The Petronas Towers were the tallest buildings in the world for six years, until Taipei 101 was completed in 2004. The height of the towers is measured to the top of their structural components such as spires, but do not include antennas. Spires are considered actual integral parts of the architectural design of buildings, to which changes would substantially change the appearance and design of the building, whereas antennas may be added or removed without such consequences. The Petronas Towers still remain the tallest twin buildings in the world.
The Petronas's height compared to some other well-known tall structures

Willis Tower (formerly Sears Tower) and the World Trade Center towers were each constructed with 110 occupied floors – 22 more than the 88 floors of the Petronas Towers. Willis Tower’s tallest antenna is 247.4 ft taller than those of the Petronas Towers, however, in accordance to CTBUH regulations and guidelines, the antennas of Willis Tower were not counted as part of its architectural features. The spires on the Petronas Towers are included in the height since they are not antenna masts. Therefore, the Petronas Towers exceed the official height of Willis Tower by 10 m.

Reff:http://en.wikipedia.org/wiki/Petronas_Towers