The Shanghai Tower is a supertall skyscraper designed by Gensler and currently under construction in the Pudong District of Shanghai. It will be the tallest of the group of three supertalls in Pudong, the other two being the Jin Mao Tower and the Shanghai World Financial Center. Upon completion, the building will rise approximately 632 metres (2,073 ft), have 128 stories, and contain an area of 380,000 m2 (4,090,000 sq ft). It will be the tallest building in China, and the second tallest in the world, surpassed only by the Burj Khalifa in Dubai. An innovative design by Marshall Strabala of Gensler was chosen in June 2008, where the building twists as it rises and is surrounded by an outer glass curtain wall. The design of the glass fa'ade is described to be able to reduce wind loads on the building by 24%, meaning less construction materials are needed, and the twisting feature will collect rainwater to be used for the tower's air conditioning and heating systems. Wind turbines will generate power for the building. According to E-Architect.co.uk, it will be the first super-tall (300 metres or taller) double-skin building in the world, acting much like a 'thermos bottle,' says Strabala, to insulate it and save energy.