Tall, taller, tallest. That honor goes to the Burj Dubai. It's more than 2,700 (more than 1/2 mile tall) feet above Dubai, United Arab Emerites and is known as vertical city. It's name is Arabic for Dubai Tower and it cost $1.5 billion. There's a hotel inside designed by Giorgio Armani and there are plans to have a mosque (the world's tallest) on the 158th floor.
The people who planned the Burj Dubai (Chicago based Skidmore, Owings a&Merrill), want it to be a monument to the spirit of Dubai which is one of seven federations that make up the United Arab Emerites. They project had bad timing due to the collapse in prices of property. A sheik from Abu Dhabi came to the rescue so that the building could be completed. It's a reinforced concrete structure which makes it stronger than steel-frame skyscrapers. It's said that a plane won't be able to slice through Burj Dubai like one did through the World Trade Center.
The tower is more than 1,00 feet taller than the Taipei in Taiwan. The Sears Tower (now the Willis Tower) is 1,451'. Both World Trade Center Towers topped 1,300 feet and The Freedom Tower being planned for the Trade Center's site will be 1,776 feet (to be completed in 2013).