Anti-War Demonstration, Atlanta, Georgia, April 18, 1970. [Note: large crowd with signs] More info
Internal opposition to American involvement in the Vietnam War began with demonstrations in 1964, but escalated substantially over subsequent years. The American public became highly polarized, between those advocating peace and those wanting to continue United States involvement in Vietnam. The opposition took many forms, ranging from peaceful demonstrations to outright violence. Public support for the war eroded as the war continued through the late 1960s and into the early 1970s. The combatant nations (United States, North Vietnam, and South Vietnam) began negotiating an end to the conflict in Paris, France, on May 10, 1968, eventually signing the Paris Peace Accords on January 27, 1973.
Sometimes the anti-war movement converged with the civil rights movement, as for example when Julian Bond was elected to the Georgia legislature but was denied his seat because he opposed the Vietnam War. Similar crossover influence can be observed in other activism venues as well.