The tallest building in the world, the Burj Khalifa (formerly known as the Burj Dubai) is due to be opened today. The Burj Dubai is 828m (2,684 ft) tall.
Unfortunately Google Maps' satellite view only shows what the location looked like before the building of the Burj began. But you needn't worry as this Google Earth plugin application allows you to view the Burj Khalifa in glorious 3D.
Viewing the skyscraper in Google Earth allows you to compare the Burj to other nearby buildings and really helps to impress upon you the amazing size of this building.