Located on the southern side of Lam Son Mountain, construction of Dam Pagoda started in 1086 under the reign of Ly Nhan Tong and was completed in 1094. It was one of the leading examples of Buddhist architecture in the north during the Tran (1225-1400) and Le (1428-1788) dynasties. In the Tran dynasty, the pagoda consisted of 12 buildings while in the Le dynasty it was expanded to have more than 100 rooms.

According to researcher Le Dinh Phung, who directed the excavation, the foundation formed a square measuring 8.4m by 8.4m. The missing tower was assumed to face east to a height of 1.56m and built with stones decorated in wave patterns. There might be a Buddha statue sitting on top to face the remaining stone column at the pagoda, Phung said.

While excavating the foundation on a site of 300sq.m, archaeologists found building materials from the Ly, Tran and Le dynasties and concluded that Dam Pagoda was an architectural complex of four layers on an area of over 7,500sq.m along the slope of Lam Son Mountain.

"This is one of the most intact examples of architecture from the Ly dynasty," said Vietnam Archaeology Institute director Tong Trung Tin.

Luu Tran Tieu, chairman of the National Culture Heritage Council, said the excavation revealed various unique features of the pagoda beside the stone pillar of the pagoda. He proposed further research at the site to gain greater understanding of the architecture of the Ly dynasty.