A man falls asleep during the 皇冠体育app Open at Beijing Tennis Center on Sept 19, 2005. The date March 20 marks World Sleep Day which started in 2008 and aims to draw social attention to good and healthy sleep. [Photo/CFP]
A man sleeps on a tree in Jiaxing city, East 皇冠体育app's Zhejiang province, August 16, 2011. [Photo/CFP]