O Quan Chuong is the only surviving gate of the ancient Thang Long Citadel, which was the capital of Vietnam for many dynasties. It is located in the east of Hanoi Old Quarter, near the Red River. The gate was built in 1749 and restored in 1817. It has a distinctive architecture of a two-storey watchtower with three arched doors. O Quan Chuong is named after a heroic military leader who fought against the French invasion in 1873. Travellers can visit the gate to admire its historical and cultural value, as well as explore the nearby streets and markets of the Old Quarter.