Introduction to the first door of the underground palace: The underground palace is 26 meters deep from the surface. The total length of the tomb passage is more than 50 meters. The total length of the tomb chamber is 20.6 meters. It is divided into two chambers, front and rear. The plane is in the shape of a "T", and the earth cover area is about 13,000 square meters. . This mausoleum, which is a huge project, was built on a mountain with stones cut out and then built with bricks, using about 200,000 cubic meters of earth and stone. The tomb passage faces south, is wide on the outside and narrows on the inside, with a slope shape that is high outside and low inside.