The long coast of the Gulf of Thailand has many sandy beaches. One of the best known, Hua Hin, has been a popular resort since King Prajadhipok (Rama VII) built a summer palace there. From the coast the land quickly rises into the Tenasserim Hills, the mountain chain that forms the border with Myanmar. Due to its narrow watershed, the rivers in the province are all small. The only one of significance is the Pranburi River in the north. Among the smaller rivers is the Khlong Kui.