The Petronas Towers' structural system is a tube in tube design, invented by Fazlur Rahman Khan. Applying a tube-structure for extreme tall buildings is a common phenomenon.
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. Another Islamic influence on the design is that the cross section of the towers is based on a Rub el Hizb, albeit with circular sectors added to meet office space requirements. The tower evoke the image of Qutb Minar.
According to the Council on Tall Buildings and Urban Habitat (CTBUH)'s official definition and ranking, they were the tallest buildings in the world from 1998 to 2004 and remain the tallest twin towers in the world. The buildings are a landmark of Kuala Lumpur, along with nearby Kuala Lumpur Tower.
The towers were designed by Argentine architect César Pelli. A distinctive postmodern style was chosen to create a 21st-century icon for Kuala Lumpur, Malaysia. Planning on the Petronas Towers started on 1 January 1992 and included rigorous tests and simulations of wind and structural loads on the design.
Seven years of construction followed at the former site of the original Selangor Turf Club, beginning on 1 March 1993 with excavation, which involved moving 500 truckloads of earth every night to dig down 30 metres (98 ft) below the surface.
Tower One is fully occupied by Petronas and a number of its subsidiaries and associate companies, while the office spaces in Tower Two are mostly available for lease to other companies.
A number of companies have offices in Tower Two, including Huawei Technologies, AVEVA, Al Jazeera English, Carigali Hess, Bloomberg, Boeing, IBM, Khazanah Nasional Berhad, McKinsey & Co, WIPRO Limited, TCS, HCL Technologies, Krawler, Microsoft, The Agency (a modelling company) and Reuters.
The towers feature a double decker skybridge connecting the two towers on the 41st and 42nd floors, which is the highest 2-story bridge in the world. It is not attached to the main structure, but is instead designed to slide in and out of the towers to prevent it from breaking, as the towers sway several feet in towards and away from each other during high winds.