Diaoyu Fortress (simplified Chinese: 钓鱼城; traditional Chinese: 釣魚城; pinyin: Diàoyúchéng) is one of the great ancient battlefields of China, located on the Diaoyu Mountain, Heyang Town, in Hechuan District, Chongqing. It is famous for its resistance to the Mongol armies in the latter half of the Song Dynasty.