Crowds practice laughing 'gymnastics' at a square in Southwest China's Chongqing municipality, Jan 31, 2012. This kind of gymnastics, created by 73-year-old retired Zhong Yunxiang, requires participants to laugh loudly along with waving their arms and clapping hands to alleviate pressure and exercise the body. Zhong started learning to laugh in various ways to ventilate his sorrowful emotion after his wife passed away and has mastered more than 20 types of laughter. He also founded a laughter club in 2007, with more than 3,000 members presently. [Photo/CFP]