Over twenty thousand people visited the pandas the first day they were on display, and an estimated 1.1 million visitors came to see them the first year they were in the United States.[6] The pandas were wildly popular and China's gift was seen as an enormous diplomatic success, evidence of China's eagerness to establish official relations with the U.S.[7] It was so successful that British Prime Minister Edward Heath asked for pandas for the United Kingdom during a visit to China in 1974. Chia-Chia and Ching-Ching therefore arrived at the London Zoo a few weeks later.[6] The panda gifted to the UK would later be the logo's inspiration for the World Wildlife Fund.[3]