Brief introduction of Laoshan border

Laoshan boundary, named Yuechengling on the map, also known as Yaoshan, is one of the five mountains. The first mountain that the Central Red Army climbed in the Long March has now become a tourist attraction. Compared with Qianshan in the Long March, nothing earth-shattering happened during the crossing, but why did so many old Red Army talk about the border of Laoshan in their memoirs, and all of them were unforgettable?