Burj Dubai to be world''s tallest building, how tall?

CHICAGO (Reuters) - In the annals of tall skyscrapers, there is no doubt that the soon-to-open Burj Dubai will be the world''s tallest. But how tall is known to only a few.

"The client (Emaar Properties PJSC) will only let us say it''s more than 800 meters (2,625 feet) tall. It''s part of the mystique of the project," he said.

Baker said the architects wondered if someone would try to figure out the slender tower''s height by measuring its shadow.

Chicago-based Skidmore developed the "buttressed core" structural system that resembles a gigantic "Y" to support the super-tall tower, which is nearly twice as tall as Skidmore''s 442-meter (1,389 feet) Willis Tower in Chicago.

The 35-year-old Willis Tower, formerly the Sears Tower and once the world''s tallest building, will be bumped down to fifth spot, according to the Council on Tall Buildings and Urban Habitat, which tracks such things. The current record-holder, the Taipei 101, will be dropped to second.

Seven of the world''s 10 tallest towers are in Asia, all built in the past 13 years.

Jan Klerks of the Council on Tall Buildings said the group has asked to know the tower''s exact height.

"We have expressed this a number of times, but if there are reasons not to disclose it, then I guess we have to do without an official number. We also do not know why they chose not to disclose the number. The only thing we are sure of is that it is the tallest building in the world, and that it is at least 800 meters," Klerks said in an email.

The Burj Dubai "really cannot be rationalized through urban scarcity and land prices," Klerks said. "As such it is very much an iconic building, aiming at those who want an iconic address."

ABOUT 164 FLOORS

Apparently, the emirate''s recent financial problems have not hurt sales of the approximately 1,100 one- to three-bedroom residences in the tower, which are "pretty much 100 percent sold out," Baker said. Those include corporate "apartments" near the summit topping out at around the 164th floor.