Photo taken on June 4, 2019 shows the panda house at Moscow Zoo in Moscow, Russia. Two giant pandas, three-year-old male Ru Yi and two-year-old female Ding Ding, arrived in Moscow in late April from China's southwestern province of Sichuan. They were formally handed over to Russia for a 15-year joint research program on Wednesday at an opening ceremony for the panda house in Moscow Zoo. (Xinhua/Bai Xueqi)