Introduction to the ruins of the Semicircular Fort Ancient Well: The ruins of the Semicircular Fort Ancient Well in the inner city are located on the east side of the park and are made of layers of red bricks. According to records, the city base here is 276 feet wide and more than 3 feet high, with a total of two floors. Among them, the upper floor has pavilions and palaces, multiple roads and multiple towers; the lower floor has round convex walls on all sides, and wells are arranged in the north and south, going down to the sea and out of the city above to prevent fire attack. Now that the inner city has been completely destroyed, only the convex wall of this section of the north wall and the ancient well still remain.