It was expanded in 1940 to 1,700 square metres. Between 1930 and 1945, the French regime kept thousands of Vietnamese patriots there, such as Le Duan; Truong Trinh; To Hieu; Van Tien Dung; Xuan Thuy; Tran Huy Lieu; Nguyen Co Trach; Mai Chi Tho; Tran Quoc Hoan; Hoang The Thien and Nguyen Van Tran, who in turn transformed the prison into a ‘revolutionary school’ to help sharpen the will of freedom fighters to liberate the nation.
The area was listed as a national relic site in 1962, and has become a tourist attraction for domestic and foreign visitors. The Hanoi leaders paid tribute and offered flowers to the late soldiers, who fought and sacrificed their lives for national independence. On the same day, the Hanoi delegation also visited the Historical Relic Site of Regiment 52 in Moc Chau town, Son La province.
