Introduction to the retaining wall: In front of the ancestral hall is a retaining wall made of huge vertical stones, with a height of 9 meters. To the left and right of the ancestral hall is a protective wall with a total length of 400 meters, a height of 8 meters, and a thickness of 3 meters. The turrets at the four corners of the retaining wall are abrupt, and there are 100 gun holes on the retaining wall and the entire retaining wall. Looking from a distance, it looks like an ancient castle standing in the vast mountains, looking particularly formidable.