The Weather Underground Organization (WUO), commonly known as the Weather Underground, was a radical left-wing domestic terror group[2] active in the late 1960s and 1970s, founded on the Ann Arbor campus of the University of Michigan. Originally called Weatherman, the group became known colloquially as the Weathermen. Weatherman organized in 1969 as a faction of Students for a Democratic Society (SDS)[3] composed for the most part of the national office leadership of SDS and their supporters.