1955- 1975

  • Polio Vaccine Created

    A study demonstrating the efficacy of the Salk polio vaccine is published. Following widespread vaccinations, the disease, which has posed a serious threat for many generations, will all but vanish.
  • First Nuclear Power Plant

    Pittsburgh receives electricity from Shippingport, Pennsylvania's first full-scale nuclear power plant.
  • First ICBM

    The first intercontinental ballistic missile was launched, according to Soviet Union officials. Four months later, the Americans will have a similar weapon ready for use.
  • Kennedy is Elected

    The youngest president is elected: John F. Kennedy. Eisenhower is disappointed by Kennedy's victory over Richard Nixon, his former running mate, in a tight election.
  • First U.S. Combat Death from War

    The first confirmed combat fatality in Vietnam involves an American service member. The death will serve as a historical marker for the Vietnam War for many Americans.
  • Vietnam Bombing

    The USS Maddox reports a second attack by North Vietnamese gunboats, though there is conflicting evidence to support this claim. President Lyndon B. Johnson issues an order for reprisals. For the first time, the United States bombs North Vietnam.
  • March on the Pentagon

    Thousands march in protest of the Vietnam War to the Pentagon.
  • MLK assassinated

    At the Lorraine Motel in Memphis, Tennessee, Martin Luther King Jr. is shot and killed. James Earl Ray, who killed him, entered a guilty plea and was given a 99-year prison term.
  • Voting Age Changed

    Ratification of the 26th Amendment results in a decrease in the national voting age to 18 from 21.