Petronas Twin Towers

The Petronas Twin Towers (also known as the Petronas Towers or Twin Towers), in Kuala Lumpur, Malaysia, were the world's tallest towers from 1998 to 2004, if measured from the level of the main entrance to the structural top, the original height reference used by the US-based Council on Tall Buildings and Urban Habitat from 1969 (three additional height categories were introduced as the tower neared completion in 1996).

These towers, which were designed by Cesar Pelli, an Argentine-American architect, were completed in 1998 and became the tallest buildings in the world on the date of completion. The 88-floor towers are constructed largely of reinforced concrete, with a steel and glass facade designed to resemble motifs found in Islamic art, a reflection of Malaysia's Muslim religion. They were built on the site of Kuala Lumpur's race track. Because of the depth of the bedrock, the buildings were built on the world's deepest foundations. The 120-meter foundations were built by Bachy Soletanche, and required massive amounts of concrete.

In an unusual move, a different construction company was hired for each of the towers, and they were made to compete against each other.

Eventually the builders of Tower 2, Samsung Constructions (the Construction Division of Samsung Corporation), Kukdong Engineering & Construction (both of South Korea), won the race, despite starting a month behind Tower 1, built by Hazama Corporation, and Tower 1(Hazama Corporation) ran into problems when they discovered the structure was 25 millimeters off from vertical. The shopping mall beneath both towers was constructed by Birmingham, Alabama based Bill Harbert International.

Due to a lack of steel and the huge cost of importing steel, the towers were constructed on a cheaper radical design of super high strength reinforced concrete. High-strength concrete is a material familiar to Asian contractors and twice as effective as steel in sway reduction; however, it makes the building twice as heavy on its foundation than a comparable steel building. Supported by 23-by-23 meter concrete cores and an outer ring of widely-spaced super columns, the towers use a sophisticated structural system that accommodates its slender profile and provides from 1300 to 2000 square metres of column-free office space per floor.

Below the twin towers is Suria KLCC, a popular shopping mall, and Dewan Filharmonik Petronas, the home of the Malaysian Philharmonic Orchestra.

Petronas, Malaysia's national oil company, set out to build the world's tallest building. Although other buildings such as the Sears Tower have higher occupied floors, a higher antenna, and a higher roof, the Petronas Twin Towers' spires are classified as architectural details and rise to 452 m (1483 feet), giving it the greatest structural height until Taipei 101. Taking advantage of the rules governing building measurements (counting spires but not antennas) has generated controversy over the towers' claim to the title. However, the tradition of including the spire on top of a building and not including the antenna dates back to the rivalry between the Chrysler building and Empire state building.

Other buildings have used spires to increase their height but have always been taller overall to the pinnacle when trying to claim the title. In the aftermath of the controversy, the rules governing official titles were partially overhauled, and a number of buildings re-classified structural antenna as architectural details to boost their height rating (even though nothing was actually done to the building). Since the rules had allowed a building that "looked" shorter to say they were taller, newer buildings have had a focus on getting more than one of the height categories and tried to cater to popular perception rather than technicalities.