Ancient China's Yangguan Pass in northwest China

Tourists dressed in ancient Chinese military uniforms pose for photos at the Yangguan scenic spot in northwest China's Gansu Province in March 2017. Yangguan, or Yangguan Pass, was fortified by Emperor Wu of the Western Han Dynasty around 120 BC. Historically, it was used as an outpost to defend enemies and was a vital pass along the ancient Silk Road. [Photo: Chinanews.com]