The grand opening for Burj Dubai, the world's tallest building, is set for January 4th 2010. It should be noted that exactly how tall Burj Dubai stands is a secret that is only known by a select few. Emaar Properties PJSC will only disclose that it's more than 2,625 feet (800 meters) tall. Because of the buildings massive height, it had to be equipped with some of the fastest elevators in the world which travel at 25mph. It will take roughly two minutes to get to the summit.