BEIJING, Sept. 18 (Xinhua) -- "The Blue Defensive Line," the first documentary about Chinese armed forces on a peacekeeping mission in an overseas war zone, hit the big screen across China Friday.

The documentary features a Chinese peacekeeping infantry battalion protecting local refugee camps in the war-torn South Sudan.

The film, shot over five years from China to Africa, is a true and vivid account of efforts made by Chinese "blue helmets" to safeguard world peace and development.

2020 marks 30 years since China's armed forces first participated in UN peacekeeping operations. Over the three decades, the country's armed forces have sent over 40,000 peacekeepers to 25 UN peacekeeping missions.