Are you supposed to make a wish after you throw in a coin? In the west, that's what I would assume. In China, I'm not so sure. In any case, I'm pretty sure that it has something to do with good luck, it's China after all.
WFC, the tallest building in Chongqing, was finished in 2014 and stands 339 meters tall. However, since it's located at a hight point, it reaches 590 meters above sea level.
Taking pictures through the window of the viewing deck of the WFC is somewhat challenging so I apologize for any ugly reflections, I did my best. Regardless, here we see Chaotianmen of the Yuzhong Penninsula in Chongqing. Pierced by Qiansimen Bridge on both sides and with the new Raffles City being constructed at the front. What a sight.