100 events that shifted history - part 4 76. Franklin Roosevelt elected president. 1932 77. Mikhail Gorbachev becomes Soviet leader, allows unprecedented freedoms. 1985 78. Max Planck proposes quantum theory. 1900 79. Scientists clone sheep in Great Britain. 1997 80. Interstate highway bill begins massive effort linking nation. 1956 81. Opening of Panama Canal. 1914 82. Betty Friedan's Feminine Mystique helps launch women's movement. 1963 83. Space shuttle Challenger explodes. 1986 84. U.S. sends troops to South Korea. 1950 85. Violence erupts outside Democratic convention in Chicago. 86. Sigmund Freud publishes Interpretation of Dreams. 1900 87. China's forced modernization program results in famines killing 20 million. 1958 [[NOTE: There would seem to be an error -- between # 75 and #87 ... who had the famines -China or USSR? Both??]] 88. U.S. enters World War I. 1917 89. Babe Ruth hits 60 home runs, a record that lasted 34 years. 1927 90. John Glenn is first American to orbit Earth. 1962 91. North Vietnamese reportedly attack U.S. ships; Congress allows use of force. 1964 92. Pathfinder robot lands on Mars. 1997 93. Hitler launches night of Nazi violence against Jews and their businesses. 1938 94. Winston Churchill becomes British prime minister. 1940 95. First "test-tube baby" born healthy. 1978 96. Soviets blockade West Berlin; Allies react with massive airlift. 1948 97. Bill Gates and Paul Allen start Microsoft Corp. 1975 98. Chernobyl nuclear plant explosion kills more than 7,000 in Soviet Union. 1986 99. Trial of teacher John Scopes in Tennessee pits creation against evolution. 1925 100. Surgeon general warns tobacco is a health hazard. 1964