1970-1979 By hankkennedy Apr 22, 1970 First Earth Day Mar 10, 1971 Senate approves 26th amendment Jun 17, 1972 The Watergate crisis begins Jan 22, 1973 Ruling on Roe vs. Wade Jan 27, 1973 Paris Peace Accords Aug 9, 1974 Nixon resigns from office Jul 20, 1976 Viking 1 Space Probe lands on Mars May 25, 1977 Star Wars Sep 21, 1977 Fifteen nations sign a nuclear-proliferation pact. Apr 18, 1978 Senate votes to return the Panama Canal back to Panama