Danish Queen Margrethe II (L) visits the Copenhagen zoo in Copenhagen, Denmark, on April 10, 2019. Danish Queen Margrethe II officially opened the Panda House at Copenhagen Zoo on Wednesday. Male Xing Er, a 5-year-old, and female Mao Sun(Mao Er), a 4-year-old, left the southwestern Chinese city of Chengdu on April 4 and headed for their new home at Copenhagen Zoo. (Xinhua/Guo Chen)