Diplomats and UN staff attend a wreath-laying ceremony at the UN headquarters in New York, on Aug. 19, 2019. The United Nations held a wreath-laying ceremony Monday to commemorate its 22 staffers killed in the 2003 attack in the Iraqi capital of Baghdad. The date was designated as World Humanitarian Day by the UN General Assembly in 2008 to mark the attack. (Xinhua/Li Muzi)