US National Zoo celebrates 'Pandaversary'

After the speeches, Smith and Qin entered the panda pavilion, placed some bamboo on a special treat for the pandas – a frozen fruit cake, with the number "50" on it.

The panda mother and son, Mei Xiang and Xiao Qi Ji, came out of their house. Mei Xiang walked steadily toward the cake while Xiao Qi Ji was playing around her. Later they ate the cake and Xiao Qi Ji rolled with the cake, leading to laughs and cheers from the crowd.

People who were lined up to see the pandas expressed love for pandas and their appreciation for the US-China panda program.

"This is my favorite animal, and I have loved them since I was a kid," said Dante, 23, who came from New Jersey and was surprised to arrive just in time for "Pandaversary". He said he was planning to find a panda shirt in the gift shop.

Helen Gonzales called panda lovers like her, who live not far and come to the zoo at least once a week to visit the pandas, the "regulars". She still remembered how the eyes of Tai Shan, the first cub born at the National Zoo, sparkled. She even went to China to revisit Tai Shan in 2011.

"It was wonderful to see him and to see how much the keeper loved him and to know that people love them over there too, which we knew in theory, but to be able to see it," Gonzales said, adding that "I miss them (the cubs) all".

"It's just wonderful to see the cooperation between China and the United States in terms of making sure that the pandas aren't going to be extinct," she told China Daily.