Hanoi last month resumed its night tour of Thang Long Imperial Citadel, a complex of buildings first constructed in 1011 under the reign of King Ly Thai To.
It was constructed on the remains of a Chinese fortress dating from the seventh century, on drained land reclaimed from Red River Delta in Hanoi.
It was the center of regional political power for almost 13 centuries, from the Ly, Tran to Le dynasties.