U.S. Democratic presidential nominee Hillary Clinton(L front), her husband and former U.S. President Bill Clinton (L back), Democratic vice presidential nominee Tim Kaine (R back) and his wife Anne Holton (R front) take the stage on the last day of the 2016 U.S. Democratic National Convention at Wells Fargo Center, Philadelphia, Pennsylvania, the United States on July 28, 2016. Former U.S. Secretary of State Hillary Clinton on Thursday formally accepted the Democratic Party's nomination for president and pledged more economic opportunities for Americans and "steady leadership". (Xinhua/Li Muzi)