Thang Long Citadel is a historic site located in Hanoi, Vietnam. It served as the political center of the country for over a thousand years, from the Ly Dynasty in the 11th century until the Nguyen Dynasty in the 19th century. The citadel is recognized for its unique architecture and cultural significance, showcasing a blend of Vietnamese and Chinese influences. In 2010, Thang Long Citadel was designated a UNESCO World Heritage Site, highlighting its importance in Vietnamese history. The site includes several notable structures, such as the Flag Tower and the Royal Palace, which reflect the rich heritage and historical events that shaped the nation.