PETRONAS TWIN TOWERS

pair of skyscraper office buildings in Kuala Lumpur, Malaysia, that are among the world's tallest buildings. The Twin Towers were built to house the headquarters of Petronas, the national petroleum company of Malaysia. They were designed by the Argentine-born American architect Cesar Pelli and were completed in 1996. The Twin Towers are identical structures that are circular in plan, contain 88 stories of occupiable space, and rise to a height of 1,483 feet (451.9 metres), a figure that includes the 242-foot- (73.6-metre-) high pinnacle atop each tower. The buildings' frames consist of high-strength, steel-reinforced concrete rather than of structural steel; 16 reinforced-concrete columns around the perimeter support each building. Each tower's exterior is sheathed in stainless steel, and a skybridge links the two towers. Upon their completion in 1996, the Petronas Twin Towers were declared the world's tallest buildings. The previous holder of this distinction was the 110-story Sears Tower in Chicago, Illinois, with a height of 1,450 feet (442 metres). The Sears Tower's roof line is actually more than 200 feet (60 metres) higher than those of the Twin Towers, but the Twin Towers' pinnacles (including their steel spires) are regarded as an integral part of the towers' architectural structure, unlike the antennae atop the Sears Tower. The spires give the Twin Towers their record-breaking height. (See Researcher's Note: Heights of Buildings.)