In a speech marking the 90th anniversary of the Long March victory, Chinese President Xi Jinping recalled how the Red Army crossed vast grasslands during its arduous journey. Ninety years ago, the marshes of southwest China tested the soldiers' endurance, as hunger, freezing conditions and treacherous terrain threatened their lives. Today, CGTN's Yang Jinghao travels into the grasslands to retrace their journey and explore the hardships they endured.