Saudi billionaire Prince Alwaleed bin Talal unveiled plans Aug. 2, 2011 to build the world's tallest tower in the Red Sea port city Jeddah
With the world's tallest tower, Burj Khalifa at the background, two boys play soccer in front of their house at the old part of Al Wasl district in Dubai, United Arab Emirates, Wednesday March 9, 2011.
(Kamran Jebreili/AP/Kamran Jebreili/AP)
Lakefront skyline of Toronto, Canada with CN Tower on left.
(Hemera Technologies/Getty Images/Hemera Technologies/Getty Images)
Clouds of rain brought by typhoon Saomai linger over the city Taipei 101, one of the world's tallest buildings on Aug. 10, 2006, in Taipei, Taiwan.
Night view of the Petronas Twin Towers in Kuala Lumpur on June 29, 2004.
(Bazuki Muhammad/Reuters/Bazuki Muhammad/Reuters)
The newly named Willis Tower is seen in the skyline of Chicago, Illinois July 16, 2009. The 36-year-old Sears, named after the world's third-largest insurance broker, Willis Group Holdings Ltd.
(Frank Polich/Reuters/Frank Polich/Reuters)
A rendering of the revised plan of the Shanghai World Financial Center building (L) is shown next to China's tallest building Jinmao Tower (R) Feb. 13, 2003.
(Claro Cortes IV/Reuters/Claro Cortes IV/Reuters)
This photo shows the reclamation work on Victoria Harbour and a view of its skyline, including the city's International Financial Center (IFC) building (back R), in Hong Kong, 26 May 2007.
(Laurent Fievet/AFP/Getty Images/Laurent Fievet/AFP/Getty Images)
The Empire State Building stands above midtown New York Sept. 1, 2010.
(Lucas Jackson/Reuters/Lucas Jackson/Reuters)
Fireworks light up Hong Kong's Victoria Harbour and Central Plaza, to celebrate the Chinese New Year February 20 1996.
(Jason Reed/Reuters/Jason Reed/Reuters)
An aerial view of the Burj Al Arab hotel in Dubai December 21, 2009.
(Matthias Seifert/Reuters/Matthias Seifert/Reuters)