Introduction to the prologue hall: Further ahead is the prologue hall. There is a preface in the hall: From October 1937 to August 1945, when the Japanese army occupied the Datong Coal Mine, they frantically plundered coal resources. Under the bloody policy of "coal", a large number of miners who were tortured to death and dying were abandoned in the wilderness, Dongtan Valley and abandoned mines, forming more than 20 mass graves filled with bones in the Datong mining area. The south entrance of Meiyu Valley is one of the most well-preserved and large-scale places. During the eight years they occupied the Datong Coal Mine, the Japanese invaders plundered a total of 14 million tons of coal, resulting in the loss of more than 60,000 miners' lives.