
The Petronas Twin Towers (also known as the Petronas Towers), in Kuala Lumpur, Malaysia, were once the world's tallest buildings when measured from the level of the main entrance to the structural or architectural top.
The Petronas Twin Towers are the tallest twin towers in the world, and they lay claim to being the world's tallest high rise of the 20th century.

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.
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-metre 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.
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 pinnacle, 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 quirks of the rules governing building measurements (counting spires but not antennas) has generated controversy over the towers' claim to the title.
Check the official Petronas Twin Tower website here. and the Suria KLCC beneath it here.