The underground is sometimes a nickname for a resistance movement: "the underground" is also a common name for World War II resistance movements . By extension, the term was also applied to counter-cultural movement(s) many of which sprang up during the 1960s. In a similar sense, the Underground Railroad was a secretive United States anti-slavery movement which helped slaves to escape repression by providing them with hiding-places and assistance in their attempts to reach freedom in Canada.