A bus with an ad featuring Giant Panda drives on Pennsylvania Avenue, in Washington D.C., capital of the United States, Sept 21, 2015. 70 metrobuses with images of six endangered animals of China: Giant Panda, Red Panda, Snub-Nosed Monkey, Tibetan Antelope, Crested Ibis and Red-Crown Crane, will travel around Northwest Washington and parts of Maryland and Virginia for five weeks since Monday. [Photo/Xinhua]