Co Loa Citadel offers glimpse into past

Co Loa Citadel, 20km north of Hanoi, appears to be the oldest such structure in Southeast Asia. The citadel was built under the reign of King An Duong Vuong (around the 2nd century BC). Its name "Co Loa" is derived from the Sino-Vietnamese for "old spiral" as the structure is built in a spiral shape.