On 3 July 1944, a train of cattle wagons set out from Toulouse, heading for Germany. Crammed inside eventually were 724 souls of various nationalities and backgrounds, all of whom the German occupiers had held captive in concentration camps and prisons across south-western France. Among them was Francesco Fausto Nitti, an Italian antifascist activist who had survived Mussolini’s gaols and the Spanish Civil War. The journey to Dachau was expected to take three days. Instead – bombed, re-routed and often immobilised – it lasted for two months, making it the longest of all deportation...