Da Nang is a major port city in the South Central Coast of Vietnam, on the coast of the South China Sea at the mouth of the Han River. It is the commercial and educational center of Central Vietnam; its well-sheltered, easily accessible port and its location on the path of the North-South Railway also makes it a hub for transportation. It is located within 100 km of several UNESCO World Heritage Sites, including the Imperial City of Huế, the Old Town of Hội An, and the Mỹ Sơn ruins. The city was also known as Tourane or Turon during the French colonization of Vietnam. Before 1997, the city was part of Quảng Nam-Đà Nẵng province. On January 1, 1997, Đà Nẵng was separated from Quảng Nam province to become one of five independent (centrally-controlled) municipalities in Vietnam. Đà Nẵng is listed as a first class city, and has a higher urbanization ratio than any of Vietnam's other provinces or centrally governed cities.