A flash mob dressed as giant pandas pose for a photo at the Chengdu International Finance Square as part of a campaign to promote local tourism on March 22. The panda squad has appeared in cities such as Wuhan, Chongqing and Shanghai to promote Fangshuijie (translated to "Drainage Day) on April 5, a holiday to commemorate the completion of the ancient Dujiangyan Irrigation System in Chengdu. Built in 256 BC on the Min River, this hydraulic engineering marvel was listed as a UNESCO World Heritage Site in 2000 and is still in use today. Photo: Chengdu Business Daily