People visit Panda Passage at Calgary Zoo in Calgary, Canada

Photo taken on July 16, 2018 shows the entrance of Panda Passage at the Calgary Zoo in Calgary, Canada. After moving to the Calgary Zoo from Toronto in March, giant panda cubs Jia Panpan, Jia Yueyue, their mother Er Shun and male adult giant panda Da Mao are expected to attract lots of visitors in the summer holiday. (Xinhua/Zou Zheng)