Ling-Ling (1969–92) and Hsing-Hsing (1970–99) were two giant pandas given to the United States as gifts by the government of China following President Richard Nixon's visit in 1972. In return, the U.S. government sent China a pair of musk oxen.
The pandas had been captured in the wild in June and December 1971. They arrived at the National Zoo in Washington, D.C., on April 16, 1972, and were formally received several days later, on April 20, at a ceremony attended by First Lady Pat Nixon. While at the zoo, they attracted millions of visitors each year.
During their time at the National Zoo, the pair had five cubs, but none of them survived past a few days.
Ling-Ling died suddenly from heart failure in December 1992, at which time she was the longest-lived giant panda in captivity outside China. Hsing-Hsing would go on to pass her record when he was euthanized by zookeepers in November 1999 at the age of 28 due to painful kidney failure. Following Hsing-Hsing's death, the zoo received thousands of letters and cards from people across the country expressing sympathy.
The Panda House at the National Zoo remained empty for over a year until the arrival of Mei Xiang and Tian Tian from the Wolong Research and Conservation Center for the Giant Panda in December 2000.