Introduction to General Pillar: In the 18th year of Hongwu, Yang Lian, the commander of Lanzhou Guard, built the famous Zhenyuan Floating Bridge at the current location of Zhongshan Bridge. According to the "River Bridge" written by Xu Lan of the Ming Dynasty, Yang Lian built 28 large ships on the Yellow River, with 3 ships in reserve. He connected the 25 ships with rope locks, fixed them with stone turtles under the ships, and added wooden boards and railings to the ships. , and built a large iron pillar and six wooden pillars on each side of the north and south sides of the bridge, and fixed the pontoon bridge with iron chains. The entire floating bridge "rises and falls with the waves, as if it were a smooth road." For more than 500 years since then, the Zhenyuan Floating Bridge has been known as the "No. 1 Bridge in the World" due to its important position in guarding the bridge. The General Iron Pillar that still stands on the south bank of the iron bridge is the only witness to the 500-year history of the rise and fall of the Zhenyuan Floating Bridge.