At Taipei City, almost all footbridges are torn down because people think their existence is not good for cityscape. Nonetheless, last Saturday when I passed the intersection of Naihai Rd. and Chongcing S. Rd., I saw a footbridge. What is more amazing is that pedestrians could only go from one side to the other side of the road via the footbridge, they are not allowed to do it via walking on the road directly. I am really curious about why pedestrians are not allowed to go from one side to the other side of the road by walking on the road directly. However, I do not know how to get the answer, and I could only take it as an unsolved mystery