The counterculture of the 1960s was an anti-establishment cultural phenomenon that developed throughout much of the Western world between the mid-1960s and the mid-1970s. The aggregate movement gained momentum as the U.S. Civil Rights Movement continued to grow, and, with the expansion of the American Government's extensive military intervention in Vietnam, would later become revolutionary to some. As the 1960s progressed, widespread social tensions also developed concerning other issues, and tended to flow along generational lines regarding human sexuality, women's rights, traditional modes of authority, experimentation with psychoactive drugs, and differing interpretations of the "American Dream". Many key movements related to these issues were born or advanced within the counterculture of the 1960s.