Thang Long Royal Citadel as relics associated with the history of Thang Long - Hanoi starting from pre-Thang Long period (Annam colonial government, VII century) through the Dinh - Tien Le dynasty, thrive under Ly, Tran, Le dynasty and under Nguyen dynasty. These are massive structures, was built in the reign many historical periods and become the most important relics in the relic system in Vietnam. Thang Long Imperial Citadel and most of the structures in Thang Long were in varying states of disrepair by the late 19th century with the upheaval of the French conquest of Hanoi. By the 20th century many of the remaining structures were torn down. Only in the 21st century are the ruin foundations of Thang Long Imperial systematically excavated. The central sector of the imperial citadel was listed in UNESCO World Heritage Site on July 31, 2010 at its session in Brazil.
