A substantial number of colliery villages were built throughout the county in the nineteenth century to house the growing workforce, which included large numbers of migrant workers from the rest of the UK. Sometimes the migrants were brought in to augment the local workforce but, in other cases, they were brought in as strike breakers, or "blacklegs". Tens of thousands of people migrated to County Durham from Cornwall (partly due to their previous experience of tin mining) between 1815 and the outbreak of the First World War, so much so that the miners' cottages in east Durham called "Greenhill" were also known locally as "Cornwall", and Easington Colliery still has a Cornish Street. Other migrants included people from Northumberland, Cumberland, South Wales, Scotland and Ireland. Coal mining had a profound effect on trade unionism, public health and housing, as well as creating a related culture, language, folklore and sense of identity that still survives today.