Following the Tây Âu conquest of the Hùng kings of Văn Lang in 258 BCE, the state of Âu Lạc was established in the Red River Delta and a new capital constructed by King Anh Dương at Cổ Loa, 16 kilometres north of present-day Hà Nội. The walls of the citadel were arranged in a spiral, the original nine coils of which covered an area of more than five square kilometres. Today there remain only the vestiges of three, which are in certain places c 2 metres high and 15 metres wide. The citadel was abandoned in 208 BCE following a Chinese invasion, but in 939 CE the site was re-occupied by Ngô Quyền and once more became the national capital. At the centre of the former citadel visitors may view a communal house and temples dedicated to King An Dương Vương (257-208 BCE) and his daughter Mỹ Châu. During excavations at the site in 1968, 1978 and 1997 a multitude of artefacts was discovered, including bronze and stone arrow heads, jewellery, utensils and kettle drums. Some 300 billion VNĐ (cUS$19 million) has been allocated by the Hà Nội authorities for restoration work at the complex between 2001 and 2009. Each lunar new year the communal house and temples host the Cổ Loa Festival: