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.
Example Usage of Underground
TMANDTM: CHECK OUT SUPERSTAR MODEL Ms. Hilayna Starr (@hilaynastarr) FEATURED ON Underground FUZION http://bit.ly/JXOMU hit up @deckent\
cavim: Better Underground : When cities reach their breaking point, life must be moved beneath the surface. China's su.. http://bit.ly/13KW9l
Vader24: Underground Alien Bases - Phil Schneider's Story (RIP) - Coast To Coast AM's MySpace Blog |: http://bit.ly/V2wSX via @addthis