The Thế Miếu, also called Thế Tổ Miếu, is an ancestral temple and was constructed on the orders of Emperor Minh Mạng in 1822-1823. It honours the emperors of the Nguyễn Dynasty. Nine dynastic urns (Vietnamese cửu đỉnh 鼎) in front of the Thế Miếu were also cast in 1822 and dedicated to the first nine Nguyen emperors. Emperor Gia Long ordered the construction of Hue Citadel in 1805. The vast complex is built according to the notions of fengshui or Chinese geomancy, but following the military principles of the noted 18th century French military architect Sebastien de Vauban. The result is an unusual and elegant hybrid, a Chinese-style Imperial City carefully aligned with surrounding hills, islands and waterways, but defended by massive brick walls between 6-12 metres high and 2.5 metres thick, punctuated by towers, ramparts, a massive earth glacis, and 24 Vauban-inspired bastions. The entire complex was further protected by wide moats, crossed by gracefully arched stone bridges leading t