U.S. Smithsonian museums, National Zoo close doors due to gov't shutdown

Birds perch on a tree in front of the Smithsonian National Museum of Natural History in Washington D.C., the United States, on Jan. 2, 2019. The 19 Smithsonian museums and the National Zoo in Washington D.C. closed their doors on Wednesday as the partial U.S. government shutdown dragged on. (Xinhua/Liu Jie)