Introduction to Baoding: Baoding is approximately circular and is a large circular mound with a diameter of about 400 meters. It is the underground palace where Zhu Yuanzhang and Empress Ma were buried together. It is surrounded by brick walls. The treasure city is thick and solid, undulating along the mountains. It is built with huge stones at the bottom and exposed bricks at the top. It is about 1 meter thick. On the south stone wall are engraved with seven characters: "This is the tomb of Taizu Ming Dynasty on this mountain". From 1998 to 1999, the Nanjing Municipal Cultural Relics Bureau and other relevant departments used advanced precision magnetic surveys to confirm that the underground palace of Zhu Yuanzhang's tomb was located below. It was deeply buried, well-preserved, and had never been stolen.