In the closing phase of the Second World War, most likely in March 1944, the manufacture of pipes by the firm of Philips was moved from the Netherlands to the Jakobsberg. Disused galleries of an old iron ore mine were developed. Such galleries run through many parts of the Wiehen Hills and Wesergebirge, their entrances are usually walled up nowadays and made unrecognisable. In Hausberge and Barkhausen there was a satellite of Neuengamme concentration camp with over a thousand prisoners, of which a considerable number worked in the Jakobsberg. Women from the area also worked, under much better conditions, in the hill. After the end of the war the local population used their surviving knowledge of the mine system running through the hills to collect material from the production facilities and sell it on the black market. The British occupation forces brought this to an end with a demolition that caused pictures to fall from the walls up to a distance of 15 kilometres away and that created part of the present-day riverside front of the Jakobsberg.