The Weather Underground was a radical left-wing organization active in the United States during the late 1960s and 1970s. Formed as a faction of the Students for a Democratic Society, it aimed to promote social change through direct action and was known for its opposition to the Vietnam War. The group engaged in protests, bombings, and other militant activities to draw attention to issues like racial injustice and anti-imperialism. The Weather Underground believed that violent resistance was necessary to achieve their goals. They sought to create a revolutionary movement and were influenced by various political ideologies, including Marxism and Leninism. Their actions led to significant controversy and legal repercussions, ultimately resulting in a decline in their activities by the late 1970s.