Tourists visit a historical exhibition at the Sino-Russian border gate in Manzhouli, north China's Inner Mongolia Autonomous Region, July 3, 2012. The border gate, being 46.6m in width and 43.7m in height, is located on the border between the Chinese frontier city Manzhouli and Baykalsk of Russia. Since the northwest frontier region of Inner Mongolia Autonomous Region became a popular travel destination in recent years, the border gate in Manzhouli attracts over two millions visitors annually. [Xinhua/Zhao Tingting]