Introduction to Shimenguan: At the northern end of Bingzhongluo Platform, there are Gaoligong Mountain and Biluo Snow Mountain running along the river. Two cliffs rise vertically from the river and soar into the sky, forming a 500-meter-high cliff. The huge stone gate is nearly 200 meters wide. The Nu River gushes out from the stone gate and rushes down. The locals call it the Nanli Wall. They also gave it a very vivid name based on the topography - Shimen Pass. Shimen Pass is not only majestic but also magnificent. It is rough and dignified, and has many beautiful folklores. It is the only way to enter and exit Yunnan and Tibet. In the early 1950s, the commanders and fighters of the 126th Regiment of the Chinese People's Liberation Army entered Tibet to defend the sacred territory of the motherland, maintain national unity, and promote social progress.