context: Jeddah Tower (Burj Jidda; formerly known as Kingdom Tower) is a skyscraper under construction in Jeddah, Saudi Arabia. [1] [2] When completed, the Jeddah Tower, one kilometer in height, would be the tallest building in the world, leaving 828 meters Burj Khalifa second. [2] The building, designed by architect Adrian Smith, was originally scheduled for completion in 2017, but the estimated completion date is now 2020. In September 2018, there will be 47 floors, less than a third, and no site activity. The building plan was published in 2004 and construction started in 2013 [3] [1]
question: What is the tallest tower in the world in 2018?
answers.text: Burj Khalifa