“I have been commissioned to give you a new life. In France, you are criminals but here I only want to see repenting men”. Such were the words of the senior superintendent of French Guiana to the first convicts who arrived on The Iles du Salut (Salvation Islands) in August 1852. The 298 common law criminals and 3 political deportees had left Brest a few weeks earlier. First of a long list, this landing of convicts marked the beginning of the most disastrous period of Guiana history and the darkest times of the French penitentiary administration system, that of penal colony which lasted one century. With open air prisons and hundreds of interdependent ramifications, each of them being organized very differently, Guiana penal colonies still captivate and are little-known. Guiana penal colonies used to be, and remain, a French Eldorado: a South American continent where people dreamt of power and wealth and yet became the endless nightmare of thousands of convicts. Penal colonies transformed French Guiana into the so-called land of “the dry guillotine”, a “path towards rottenness” where all “prison sentences” were in fact life sentences. Out of 70,000 men sent to penal colonies, less than 9,000 survived their sentences.