The Shanghai Tower, which is under construction, has reached 501.3 meters, April 11, 2013. [Photo/Xinhua]

Poised to become China's tallest skyscraper, the tower will be 632 meters in height when completed in December 2014, and will be the world's second-tallest building after the Burj Khalifa tower in Dubai.

Hang Yingwei, president of Shanghai Construction Group Co Ltd, said the tower will break many world records.

"This is the first time a tower weighing 850,000 tons is built on a soft soil foundation," he said in the news conference. "A total of 270 wind-driven generators will be installed on the 570m-high 124th floor, which will be the world's highest wind generators."

Hang said the company had to overcome many technical difficulties during the construction and that the biggest challenge will be pumping concrete to the aerial construction zone as the height increases.

Ge Qing, general engineer of the tower, said that there will be an outdoor sightseeing space on the 121st floor.

"We'll also have 21 hanging gardens to help alleviate the psychological discomfort that visitors may feel in the super tall building," Ge said.