Cổ Loa Citadel (Vietnamese: Thành Cổ Loa) is a citadel in present-day Hanoi's Dong Anh district, about 16 kilometers (10 mi) northeast of downtown. It was erected during the end of the Hồng Bàng Dynasty (about 257 BCE). The fortress is a spiral-shaped complex of the then new capital.
Latitude: 21° 06' 48.27" N
Longitude: 105° 52' 23.54" E