Nanyu Castle is Qi mei's defense installation used to fight off foreign attacks in the early days, on the inside of the arch basaltic door, there is a "Nanyu Castle Refurbishment Record" tablet embedded. The entire Nanyu Castle was built by basalt rocks, with a square and grandeur layout, and the arched castle gate reveals a slight scent of the old days; in the evening, basked in the soft sunset, there is even a sense of romanticism to it.