The discovery was announced at a on November 24 workshop, jointly held by the Institute of Archaeology and the Provincial Culture and Information Department.

Researchers said the excavated part of the vestige of the Tay Do Nam Giao altar has a spectacular structure. They said the altar has many platforms with its east, west and north sides surrounded by stone walls and its south side leaning on a wall created by a range of mountains. This special design has not been found in other altars to date.

Archaeologists said the altar vestige contributes to a greater understanding of the Ho Dynasty and the history of Thang Long-Hanoi.

In the first excavation in 2005, archaeologists found a vestige of relic foundations and steps that they confirmed were part of the Nam Giao altar platform of the Ho Dynasty.

The new discovery will build on existing evidence about the Ho Dynasty’s cultural dossier which will be presented to the United Nations Educational, Scientific and Cultural Organization (UNESCO) for Nam Giao altar’s platform as recognition of a world cultural heritage site.