The "New Century Global Center" building opens to the public in Chengdu, southwest China's Sichuan province on June 28, 2013. The center, claimed by Chinese officials to be "the world's largest standalone structure", measuring 500 meters in length and 400 meters in width, with 1.7 million square meters of floor space -- big enough to hold 20 Sydney Opera Houses -- is the latest symbol of China's economic boom.