Introduction to Dinghai City: Dinghai City is located on the beach at the back gate of Yaqimen. It is one of the main attractions in Zhoushan where the movie "The Opium War" was filmed. The entire city wall is 230 meters long, 12 meters wide, and the highest point is 12 meters. It is equipped with towers, ancient gun emplacements, arrow stacks, flagpoles and other facilities, cornices, black tiles and red walls. The entire city wall is simple, elegant and majestic.