Truong Luy, which means long rampart, was built in the 17th century and, 200km in length from north to south, covers eight districts of the southern province of Quang Ngai and two districts of the central province of Binh Dinh, along the Truong Son mountain range.

Built from a combination of soil and stone, Truong Luy has long been considered as one of Asia's largest ramparts, including fortifications, roads and military posts.

A recent workshop on the historical significance of the long rampart, in terms of economic and ethnic relations, was held in Quang Ngai Province with the participation of domestic and foreign researchers from the Viet Nam Archaeology Institute and the L'Ecole Francaise d'Extreme Orient (the Far East Archaeological Research Institute).

Director of the Quang Ngai Department of Culture, Sports and Tourism, Nguyen Dang Vu, said Truong Luy was built for the purpose of defence and to promote trade between the Kinh and the Ho Re ethnic groups.

Professor Christopher Young, head of International Advice at English Heritage, said "Truong Luy presents an enormous opportunity for research, careful conservation and sustainable use."

Prof Young suggested solutions in conserving the heritage as well as ways of developing tourism which, he added, while increasing profits, could cause irreparable damage if no management policies are put in place.

According to researchers, the rampart played a significant role, not only in ensuring local security, but also in facilitating cultural and socio-economic development in the region, as it served as both a foundation for administrative management and a gathering site for traders.

Lung Lo Pass, situated in the northern province of Yen Bai, was also recognised as a national heritage by the ministry of culture.

During the First Indochina War, the 15km-long Lung Lo Pass, used by the Vietnamese resistance force to transport weapons, goods and food during the Dien Bien Phu campaign of 1954, was heavily bombed by the French in order to sever the front lines from the rear.

Nowadays, the pass has become one of the key tourist sites of the northern mountainous region.