Hue Citadel is a historic fortress located in Hue, Vietnam. Built in the early 19th century, it served as the imperial city for the Nguyen Dynasty. The citadel is known for its impressive architecture, including walls, gates, and palaces, all designed to reflect traditional Vietnamese culture. The citadel is a UNESCO World Heritage Site, recognized for its cultural significance and historical value. Visitors can explore various structures within the complex, such as the Forbidden Purple City and the Imperial City, which showcase the grandeur of Vietnam's royal past.