chronology: the road to the nuclear age
1917
•May 25 German warplanes bomb Folkestone, Britain, killing ninety-five civilians.
1937
•April German Condor Legion bombs Basque town of Guernica in Spanish Civil War.
•August-October Japanese bomb residential neighborhoods of Shanghai.
•November Japanese troops terrorize civilian population in “Rape of Nanking.”
1938
•March German Condor Legion bombs Barcelona in support of fascist rebels.
1939
•September German warplanes bomb Warsaw to support invasion of Poland.
•September Nazi Germany launches effort to develop an atomic bomb.
•October Albert Einstein and Leo Szilard recommend to President Roosevelt that the United States fund research on developing an atomic bomb.
1940
•May German bombers destroy the city center of Rotterdam in the Netherlands, killing more than one thousand civilians.
•May American scientists isolate and identify the first element made by humans, neptunium, element 93
•September Germans begin nine-month air war against Britain, eventually dropping a total of 18,800 tons of explosives. Nazi air attacks claim 20,000 civilian lives in London and 24,000 elsewhere in Britain.
•November Fourteen German bombers drop 450 tons of explosives on the medieval British city of Coventry, killing 380 civilians.
1941
•January 19 President Roosevelt approves government funding for program to develop an atomic bomb.
•January-February American scientists isolate and identify the second element made by humans, plutonium, element 94.
•December 7 Japanese warplanes launch a surprise attack from aircraft carriers in the Pacific against the U.S. Pacific Fleet at Pearl Harbor, Hawaii.
1942
•August U.S. Army establishes the Manhattan Project (officially the Manhattan Engineer District) to oversee development of an atomic bomb.
•September 17 General Leslie Groves is given command of the Manhattan Project.
•October 19 Groves appoints J. Robert Oppenheimer to direct research efforts to develop an atomic bomb.
•December 2 First self-sustaining nuclear chain reaction is achieved at the University of Chicago.
1943
•January Allies agree they will demand unconditional surrender from the Axis powers.
•February 27 Allied commandos raid Nazi heavy water plant in Vemork, Norway.
•Spring Facilities are constructed at Oak Ridge, Tennessee, to produce fuel for an atomic bomb by separating the U-235 isotope from the U-238 isotope.
•Summer Construction begins on atomic piles at Hanford, Washington, designed to produce plutonium for an atomic bomb.
•July 24-28 Allies drop ten thousand tons of explosives to generate a firestorm in Hamburg, Germany, killingmore than forty-five thousand civilians.
•October 6 Physicist Niels Bohr arrives in Britain after fleeing Nazi-occupied Denmark.
1944
•July Twenty-two thousand Japanese civilians kill themselves in a mass suicide on Saipan after U.S. marines capture the island and neighboring Tinian.
•December 17 Plutonium production begins at Hanford, Washington.
1945
•February Scientists at Los Alamos finalize design for an implosion bomb to be fueled by plutonium.
•February 13 Allied bombers produce a firestorm in Dresden, Germany, killing one hundred thousand civilians.
•February-March Nearly five thousand U.S. and more than eighteen thousand Japanese soldiers die before American forces capture Iwo Jima.
•March 10 U.S. bombers drop two thousand tons of incendiary explosives on Tokyo to ignite a firestorm that kills more than one hundred thousand civilians.
•Spring U.S. victory on Okinawa claims the lives of 185,000 Japanese and 12,500 American soldiers—the highest death toll of the Pacific island campaign.
•April 12 Franklin Roosevelt dies in office, leaving the presidency to Harry Truman.
•April U.S. troops capture German supplies of uranium ore, a German atomic pile, and most of Germany’s atomic scientists.
•May 1 Interim Committee formed to advise President Truman on atomic weapons.
•May 8 Germany surrenders unconditionally to the Allies.
•July 16 First atomic bomb, code-named “Trinity,” is successfully tested in New Mexico.
•July 24 President Truman approves directive ordering the dropping of atomic bombs against Japan.
•July 26 The leaders of the United States, Britain, and China issue the Potsdam Declaration, threatening “prompt and utter destruction” if Japan does not immediately accept unconditional surrender.
•August 6 The United States drops an atomic bomb fueled with U-235 on Hiroshima. The bomb, code named “Little Boy,” yields an explosive force equivalent to 12,500 tons of TNT and kills approximately 100,000 people.
•August 8 The Soviet Union declares war against Japan and invades northern China the following day.
•August 9 The United States drops an atomic bomb fueled by plutonium on Nagasaki. The bomb, code named “Fat Man,” yields an explosive force equivalent to twenty-two thousand tons of TNT and kills approximately seventy thousand people.
•August 14 Japan announces its surrender.
•May 25 German warplanes bomb Folkestone, Britain, killing ninety-five civilians.
1937
•April German Condor Legion bombs Basque town of Guernica in Spanish Civil War.
•August-October Japanese bomb residential neighborhoods of Shanghai.
•November Japanese troops terrorize civilian population in “Rape of Nanking.”
1938
•March German Condor Legion bombs Barcelona in support of fascist rebels.
1939
•September German warplanes bomb Warsaw to support invasion of Poland.
•September Nazi Germany launches effort to develop an atomic bomb.
•October Albert Einstein and Leo Szilard recommend to President Roosevelt that the United States fund research on developing an atomic bomb.
1940
•May German bombers destroy the city center of Rotterdam in the Netherlands, killing more than one thousand civilians.
•May American scientists isolate and identify the first element made by humans, neptunium, element 93
•September Germans begin nine-month air war against Britain, eventually dropping a total of 18,800 tons of explosives. Nazi air attacks claim 20,000 civilian lives in London and 24,000 elsewhere in Britain.
•November Fourteen German bombers drop 450 tons of explosives on the medieval British city of Coventry, killing 380 civilians.
1941
•January 19 President Roosevelt approves government funding for program to develop an atomic bomb.
•January-February American scientists isolate and identify the second element made by humans, plutonium, element 94.
•December 7 Japanese warplanes launch a surprise attack from aircraft carriers in the Pacific against the U.S. Pacific Fleet at Pearl Harbor, Hawaii.
1942
•August U.S. Army establishes the Manhattan Project (officially the Manhattan Engineer District) to oversee development of an atomic bomb.
•September 17 General Leslie Groves is given command of the Manhattan Project.
•October 19 Groves appoints J. Robert Oppenheimer to direct research efforts to develop an atomic bomb.
•December 2 First self-sustaining nuclear chain reaction is achieved at the University of Chicago.
1943
•January Allies agree they will demand unconditional surrender from the Axis powers.
•February 27 Allied commandos raid Nazi heavy water plant in Vemork, Norway.
•Spring Facilities are constructed at Oak Ridge, Tennessee, to produce fuel for an atomic bomb by separating the U-235 isotope from the U-238 isotope.
•Summer Construction begins on atomic piles at Hanford, Washington, designed to produce plutonium for an atomic bomb.
•July 24-28 Allies drop ten thousand tons of explosives to generate a firestorm in Hamburg, Germany, killingmore than forty-five thousand civilians.
•October 6 Physicist Niels Bohr arrives in Britain after fleeing Nazi-occupied Denmark.
1944
•July Twenty-two thousand Japanese civilians kill themselves in a mass suicide on Saipan after U.S. marines capture the island and neighboring Tinian.
•December 17 Plutonium production begins at Hanford, Washington.
1945
•February Scientists at Los Alamos finalize design for an implosion bomb to be fueled by plutonium.
•February 13 Allied bombers produce a firestorm in Dresden, Germany, killing one hundred thousand civilians.
•February-March Nearly five thousand U.S. and more than eighteen thousand Japanese soldiers die before American forces capture Iwo Jima.
•March 10 U.S. bombers drop two thousand tons of incendiary explosives on Tokyo to ignite a firestorm that kills more than one hundred thousand civilians.
•Spring U.S. victory on Okinawa claims the lives of 185,000 Japanese and 12,500 American soldiers—the highest death toll of the Pacific island campaign.
•April 12 Franklin Roosevelt dies in office, leaving the presidency to Harry Truman.
•April U.S. troops capture German supplies of uranium ore, a German atomic pile, and most of Germany’s atomic scientists.
•May 1 Interim Committee formed to advise President Truman on atomic weapons.
•May 8 Germany surrenders unconditionally to the Allies.
•July 16 First atomic bomb, code-named “Trinity,” is successfully tested in New Mexico.
•July 24 President Truman approves directive ordering the dropping of atomic bombs against Japan.
•July 26 The leaders of the United States, Britain, and China issue the Potsdam Declaration, threatening “prompt and utter destruction” if Japan does not immediately accept unconditional surrender.
•August 6 The United States drops an atomic bomb fueled with U-235 on Hiroshima. The bomb, code named “Little Boy,” yields an explosive force equivalent to 12,500 tons of TNT and kills approximately 100,000 people.
•August 8 The Soviet Union declares war against Japan and invades northern China the following day.
•August 9 The United States drops an atomic bomb fueled by plutonium on Nagasaki. The bomb, code named “Fat Man,” yields an explosive force equivalent to twenty-two thousand tons of TNT and kills approximately seventy thousand people.
•August 14 Japan announces its surrender.