Co Loa Citadel

Co Loa was built around the third century BC as the capital of Au Lac under An Duong Vuong, and its plan was three concentric ramparts of rammed earth with moats between them, laid out in an irregular spiral - the outer circuit runs several kilometres and substantial sections are still standing as banks between the fields, which makes it one of the oldest surviving earthwork settlements in South East Asia. Excavation has produced very large quantities of bronze arrowheads. The legend attached explains the fall of the citadel through a magic crossbow and the king's daughter My Chau, and temples to both stand inside the walls.

What you actually see

• Three concentric earth ramparts - from about the third century BC.
• Sections still standing - as banks in the surrounding fields.
• Bronze arrowheads in quantity - from the excavations.
• Temples to the king and My Chau - inside the circuit.

When to go

Year round; the festival is in the first lunar month. Half a day.

Honest expectations

The ramparts read as low banks and take some effort to make out - a plan helps. Modern building has gone up across parts of the site. Interpretation is limited and mostly in Vietnamese. The temples are the visible part.

Nearby

Hanoi is south; the Red River runs between.