Giant panda "Ping Ping" plays as people celebrate the birthday of giant panda twins "Ping Ping" and "An An" at the Bifengxia breeding base in Ya'an City of southwest China's Sichuan Province, July 6, 2009. [Jiang Hongjing/Xinhua]
![Giant panda 'Ping Ping' plays as people celebrate the birthday of giant panda twins 'Ping Ping' and 'An An' at the Bifengxia breeding base in Ya'an City of southwest China's Sichuan Province, July 6, 2009. [Jiang Hongjing/Xinhua]](http://images.china.cn/attachement/jpg/site1007/20090707/000bcdb95f1d0bbcddc904.jpg "Giant panda 'Ping Ping' plays as people celebrate the birthday of giant panda twins 'Ping Ping' and 'An An' at the Bifengxia breeding base in Ya'an City of southwest China's Sichuan Province, July 6, 2009. [Jiang Hongjing/Xinhua]")
