First Lesson: Chinese mountaineering team built human ladder to world's highest peak

At 8,600 meters above sea level on the northern slope of the world's highest peak Mt. Qomolangma, there is a 30-meter high, almost vertical cliff. In 1975, Chinese climbers erected a metal ladder there that was nicknamed the "Chinese Ladder." The story was told by a man who helped build the ladder, Xia Boyu. 

According to Xia, the first ladder was actually a human one. In 1960, when the Chinese team first climbed Mt. Qomolangma, they had to step on each other's shoulders to reach the top because of a lack of resources. It was 4:20 a.m. on May 25, 1960, when the national flag of the People's Republic of China was seen fluttering above the world's highest peak for the first time.