Aerial photo taken on June 18, 2018 shows a bullet train maintenance base in Nanning, south China's Guangxi Zhuang Autonomous Region. Starting from zero, the total length of operational high-speed rail tracks in Guangxi has hit 1,751 kilometers in the recent five years. By 2020, the autonomous region expects to expand its high-speed railway network to over 2,000 kilometers. (Xinhua/Huang Xiaobang)