Tangdao Bay is surrounded by two capes, and the mouth of the bay is the famous Tang Island. Tang Island is very small, only 0.07 square kilometers, but it is very famous. According to legend, during the Tang Dynasty, Tang Taizong personally led the navy to expedition east and once stationed on this island, so it was called Tang Island. Many ancient weapons such as knives, swords and arrowheads were unearthed on the island many years ago. However, the existing historical data cannot prove that Emperor Taizong of Tang actually stationed navy here, and a famous naval war in Chinese history did occur here during the Southern Song Dynasty.