Labor unions were created to protect workers' rights. In the late 19th century, unions grew as the country became more industrialized and immigrant populations flooded to cities in search of work.Strikes were common, as workers and their unions sought better hours, higher pay, and safer conditions. This Union membership card belonged to John Kittelson of Minneapolis, a member of the Brotherhood of Locomotive Firemen and Enginemen. During World War I, the government was suspicious of many labor unions, and arrested labor radicals.