More than 400 people boarded the missile destroyer Qingdao during an open day held by the North Sea Fleet of the Chinese navy, in Qingdao, East China's Shandong province, Dec 25, 2013. The open day marks the fifth anniversary of China's naval escort mission, which has helped more than 5,000 ships at home and abroad since 2008. [Photo by Xu Chongde/Asianewsphoto]