Khaleejia said: Khalifa Tower has been finished and officially opened on 4th January 2010. It took 5 years to build the tower. Now Burj Khalifa (formelly known as Burj Dubai- Dubai Tower) is the tallest building in the world 828 m high. Dubai's ruler renamed the tower Burj Khalifa after the president of the UAE and the ruler of the emirate of Abu Dhabi. So now it's Burj Khalifa :)
Bellow are two nice videos of the grand opening ceremony.