Designed by Argentine-American architect César Pelli, the Petronas Towers were completed in 1998 and became the tallest buildings in the world on the date of completion. 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.

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).