The main sights on Con Son Island include a museum, several French and American-era prisons and a sombre cemetery. The only place that advertises entrance tickets is Phu Hai Prison but this should cover all other sights according to the theory.
Revolutionary Museum is next to Saigon Con Dao Hotel and has exhibits on Vietnamese resistance to the French, communist opposition to the Republic of Vietnam, and the treatment of political prisoners (including some gruesome photos of torture). There is also a mock-up of the islands and some curiously embalmed animals, including a monkey smoking a pipe. An impressive-looking new Con Dao Museum is located at the eastern end of Ð Nguyen Hue and exhibits from the Revolutionary Museum will be moved here once it opens its doors.
Phu Hai Museum, a short walk from the museum, is the largest of the 11 prisons on the island. Built in 1862, the prison houses several enormous detention buildings, one with about 100 shackled and emaciated mannequins that are all too lifelike. Equally eerie are the empty solitary cells with ankle shackles (the decree on the walls in Vietnamese means 'no killing fleas', as prisoners were not allowed to dirty the walls). Nearby is the equally disturbing Phu Son Prison.
The notorious Tiger Cages were built by the French in the 1940s. From 1957 to 1961 nearly 2000 political prisoners were confined in these tiny cells. Here there are 120 chambers with ceiling bars, where guards could watch down on the prisoners like tigers in a zoo, and another 60 solariums with no roof at all.
Over the course of four decades of war, some 20,000 people were killed on Con Son and 1994 of their graves can be seen at the peaceful Hang Duong Cemetery , located at the eastern edge of town. Sadly, only 700 of these graves bear the name of the victims. Vietnam's most famous heroine, Vo Thi Sau (1933–52), was the first woman executed by a firing squad on Con Son, on 23 January 1952. Today's pilgrims come to burn incense at her tomb, and make offerings of mirrors and combs, symbolic because she died so young. In the distance behind the cemetery you'll see a huge monument symbolising three giant sticks of incense.
Phu Binh Camp is also part of the main prison circuit, though it's on the edge of town. Built in 1971 by the Americans, this one has 384 chambers and was known as Camp 7 until 1973, when it closed following evidence of torture. After the Paris Agreements in 1973, the name was changed to Phu Binh Camp. Watch out for bats nesting among the silent cells.