This prison was built by the French at the turn of the 20th century, in classical French prison design. This is where the French imprisoned and executed Vietnamese freedom fighters. It is now a museum since two thirds of the prison was torn down to make way for the Hanoi Towers, the museum exhibits the plight of the jailed political revolutionaries, their plight under the French colonial regime and the struggle of the Vietnamese people against imperialism in chilling detail. The prison was also known as the "Hanoi Hilton" during the Vietnam War as it held US POWs. Little emphasis is given to this period however, and to some the exhibits may seem to be propaganda, such as showing photos only of prisoners being treated well and playing basketball and playing chess. The museum claims to have John McCain's flight suit from when his plane was shot down. Most of the exhibits are self-explanatory in English and a guide may not be required. You can still get one for 25,000 dong.