Designed by an Argentine architect as the headquarters of the oil and gas firm Petronas, this iconic pair of buildings looks as sleek as the day it was completed in 1998. The facade of glass and steel was inspired by Islamic art motifs, and the structures’ five tiers represent Islam’s five pillars. At 452 meters (1,483 feet), they are the world’s tallest twin towers. The 370-meter-high (1,213-foot-high) observation deck on the 86th floor is one of KL’s most popular sites.