Co Loa Citadel was the “first fortified citadel in Vietnamese history,” explains Lonely Planet. Located 16km north of the Old Quarter, it “became the national capital during the reign of Ngo Quyen (AD 939–44),” but only “vestiges of the ancient ramparts” remain. The “ancient, spiral-shaped citadel dates back to the third century BC,” writes Travelfish, but the few ancient ramparts remaining are “hard to spot among the more recent construction.”
There’s a sixteenth-century black-bronze statue of the king on the main altar, “resplendent in his double crown” inside the rebuilt temple, notes Rough Guides, but more interesting, is the second group of buildings, “where a large, walled courtyard contains a beautifully simple open-sided hall, furnished with huge, ironwood pillars, and containing some of the archeological finds.”