Northeast Vietnam is mountainous forestland including Lang Son, Cao Bang, Quang Ninh, Lao Cai, Bac Kan, Tuyen Quang, Thai Nguyen, and Ha Giang. Ethnic groups living here are Tay, Nung, H 'Mong, Dao, and Chinese, in which Tay is the most populous and oldest natives in this region. Ha Giang borders China in northern Vietnam with a fantastic landscape of limestone and granite mountains. Hoang Su Phi is a district of Ha Giang, about 300km away from Hanoi. The terrain of the area is primarily steep mountains alternating with deep valleys and primary forests. One of the most spectacular wonders of Hoang Su Phi is the rice terraces, which have recognized as a National Heritage in 2012. On the spiral mountain roads between Yen Minh and Dong Van, before crossing the Mai Pi Leng Pass to Meo Vac on spiral mountain roads. Here is where the most spectacular scenery in the country and the most conical mountains shape. Further to the East, Ban Gioc Waterfall in Cao Bang, just a tiny river cross to China territory. It's the most country's stunning waterfall. Ha Long Bay has around 1,553 km2, including 1,960–2,000 islets, most of which are limestone. The Bay is a World Natural Heritage Area for its exceptional scenic beauty and one of the world's greatest natural wonders by the Gulf of Tonkin.