The United Nations Educational, Scientific and Cultural Organization (UNESCO) has designated a citadel, built over 600 years ago in the central province of Thanh Hoa, as a World Heritage Site.
Covering over 769 square meters in Vinh Tien and Vinh Long communes, the citadel, also known as the Tay Do (Western Capital) Citadel, has an average height of between seven and eight meters, with some points reaching ten meters.
It has entrances on all sides, but the main one is in the south, with the biggest of its three grates stretches nearly six meters wide.
Historical documents show that the citadel was built in 1397 as ordered by Ho Quy Ly, the highest-ranking general of the Tran Dynasty (1225-1400) who dethroned King Tran Thieu De to establish the Ho Dynasty (1336-1407).
It was built with green block granite, some of which are 1.3 meters high and 1.59 meters wide. The rocks weighing thousands of kilograms were placed without any adhesive substance.
The work was said to be manually built in three months, while the rocks were brought from many places by road or river.
Since 2004 Vietnam Institute of Archaeology, in cooperation with Thanh Hoa Province, has excavated the site and found several artifacts within the citadel.
One of them is the three-storied Nam Giao dais built in 1402, where the king conducted prayers for peace and happiness for the country and its citizens.
The Ho Dynasty's citadel is the ancient capital of Vietnam with historical and cultural significance, and also a work with architecture that is unique in Southeast Asia, Do Quang Trong, head of the management board of the Ho Dynasty vestige site, said in an interview with Thanh Nien.