Nha Trang ( or ; ) is a coastal city and capital of Khánh Hòa Province, on the South Central Coast of Vietnam. It is bounded on the north by Ninh Hoà town, on the south by Cam Ranh city and on the west by Diên Khánh District. The city has about 392,000 inhabitants, a number that is projected to increase to 560,000 by 2015 and 630,000 inhabitants by 2025. An area of of the western communes of Diên An and Diên Toàn is planned to be merged into Nha Trang which will make its new area based on the approval of the Prime Minister of Vietnam in September 2012. Nha Trang is well known for its beaches and scuba diving and has developed into a popular destination for international tourists, attracting large numbers of backpackers, as well as more affluent travelers on the south-east Asia circuit; it is already very popular with Vietnamese tourists, with Nha Trang Bay widely considered as among the world's most beautiful bays. Tourists are welcomed to participate in the Sea Festival, held biennially. Historically, the city was known as Kauthara under rule of the Kingdom of Champa. The city is still home to the famous Po Nagar Tower built by the Champa. Being a coastal city, Nha Trang is a centre for marine science based at the Nha Trang Oceanography Institute. The Hon Mun marine protected area is one of four first marine protected areas in the world admitted by the IUCN. Etymology According to some researchers, the name Nha Trang derives from a Vietnamese spelling of the Cham language name of the site Ea Dran (literally "Reed River"), the name of the Cai River as referred to by the Cham people. From the name of this river, the name was adopted to call what is now Nha Trang, which was officially made Vietnam's territory in 1698. Ea Dran is a common Cham and Montagnard place name, same as Ia Drang Valley. As far as the recorded naming of Nha Trang is concerned, in Toàn tập Thiên Nam Tứ Chí Lộ Đồ Thư, a geographical book written by a Vietnamese scholar with the family of Đỗ Bá in the second half of the 18th century, the name Nha Trang Môn ("Nha Trang gate") was mentioned. In another map dating to the 17th century, known as Giáp Ngọ Niên Bình Nam Đồ by a noble