Female giant panda Bai Yun, 27, and her son, 6-year-old Xiao Liwu, returned to China on Thursday after the conservation loan agreement with the San Diego Zoo ended. /VCG Photo

Bai Yun arrived at the San Diego Zoo in 1996, and gave birth to her son, whose name translates to "Little Gift" in English. /VCG Photo

The two pandas arrived at the Dujiangyan Base of the China Conservation and Research Center for Giant Pandas on Thursday morning in good condition. /VCG Photo

During the 23-year scientific cooperation with the San Diego Zoo, the center has gained achievements in protection, breeding, disease control of giant pandas and related public education. /VCG Photo