People visit the Ping'anli Station of Beijing Subway Line 4 in Beijing, capital of China, on May 31, 2009. Beijing Subway Line 4 of about 28 kilometers began test operation on May 31. It will be put into use at the end of September. [Xinhua]

Photo taken on May 31, 2009 shows a view of the Zhongguancun Station of Beijing Subway Line 4 in Beijing, capital of China. Beijing Subway Line 4 of about 28 kilometers began test operation on May 31. It will be put into use at the end of September. [Xinhua]