People walk by the CN Tower and the Rogers Centre before the Buffalo Bills play the Washington Redskins in their NFL football game in Toronto, October 30, 2011.The CN Tower is a communications and observation tower in Downtown Toronto, Ontario, Canada, Standing 553.3 metres high, which was completed in 1976, becoming the world's tallest tower till the construction of Guangzhou Tower.[Photo/Agencies]

Ostankino Tower is a free-standing television and radio tower in Moscow, Russia. Standing 540 meters high, It is a member of the World Federation of Great Towers, currently the tallest in Europe and 4th tallest in the world.[Photo/Agencies]

The Oriental Pearl Tower is pictured through a glass wall as people walking past and the skyline behind are reflected on the wall in the financial district of Pudong in Shanghai Nov 22, 2011.The Oriental Pearl Tower is a TV tower, standing 467.9 meters high completed in 1994. It will rank 5th in height after the completion of the Tokyo Sky Tree in May 22, 2012. [Photo/Agencies]