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.
These towers, which were designed by architect César Pelli, 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.