Introduction to the city wall: Visitors go up the mountain and climb to a high platform. They are surrounded by city walls and have a broad view. The tall beacon tower records the vicissitudes of history. Leaning on the railing, you can see the blue sea and blue sky as far as the eye can see. Under the sunlight, the waves sparkle. Flocks of seagulls glided nimbly across the water, and white sails and fishermen's boats floated on the vast ocean.