During the German occupation of Alderney from 1940 to 1945, the island housed four forced-labour camps: Lager Borkum, Lager Helgoland, Lager Norderney, and Lager Sylt. The population had been evacuated to Britain before the Germans arrived, leaving an empty island that was intensively fortified and used as a forced-labour site. The camps held thousands of workers — mainly Soviet prisoners of war, Jews transported from across occupied Europe, and workers from the Organisation Todt — who built the island's fortifications under brutal conditions.
The camps themselves no longer stand, but their sites are marked and accessible. Lager Sylt, on the southwest of the island, has the most visible remains: the gateway arch survives and is now a memorial site. The Alderney Society Museum in St Anne houses an exhibition on the occupation period that provides essential context. The full history of what happened here was suppressed for decades and remains contested; academic research has established that mortality rates were very high.