Co Loa Citadel

Co Loa Citadel is a fortified settlement in Dong Anh District with three concentric walls linked by moats. The earthen ramparts sweep in wide curves and enclose rice paddies, villages and ponds.

The complex arose in the third century BCE as the capital of the Au Lac kingdom under King Thuc Phan. Later generations expanded the outer defense lines before the center moved to other regions.

The name translates literally as "snail citadel" and reflects the coiled layout of the fortifications. Locals still visit the central temple area to honor An Dương Vương during festivals.

The site lies north of Hanoi and can be reached by car or local buses. Visitors should wear comfortable shoes, as the paths run over uneven ground between the ramparts.

Archaeologists uncovered a large bronze drum from the Dongson culture that was involved in ceremonial rituals. The inner areas also contain workshop remains where weapons and tools were forged.