PETRONAS TWINS TOWERSPetronas Towers, also known as Petronas Twin Towers, are twin buildings situated in Kuala Lumpur, Malaysia it were designed by Argentine architect Csar Pelli .the construction of the towers began in 1992 and completed in 1998. With 88 floors, mostly concrete structure, steel, aluminum and glass (front),honoring the Muslim heritage of Malaysia. it was constructed with an Islamic art.It took 6 years of 24 hour construction to complete the twin towers. The building costs were US $ 1,8 billion and It took three days to lift the Skybridge up to the 41st/42nd floor.The architect was an Argentinian; the consultants were from Canada, the structural design engineers were from New York and lastly two consortiums were hired one from Japan and the other from South Korea- Petronas Twin Towers were the tallest buildings in the world until 2004, when Taipei 101 took over the title. the biggest challenge they had was the construction barriers. first they had to build a strong base, also they had to overcome the weather change during the construction.