January 26, 1939. Franco’s Spanish Nationalist troops, aided by Italy, take Barcelona.

January 28, 1939. German physicists Otto Hahn and Fritz Strassman find a way to bombard uranium atoms with neutrons until the atoms split, releasing huge amounts of energy in the process. Hahn calls the discovery “nuclear fission”. It may be possible to use the energy produced by this process to make a bomb that will have immense destructive power.

March, 1939. Swiss company Nestle launches a new product in the United Kingdom, instant coffee.

March 15, 1939. Hitler enters Prague, Czechoslovakia as the German army takes over the remainder of the country.

August 23, 1939. Molotov-Ribbentrop Pact, Adolf Hitler and Joseph Stalin sign a non-aggression pact and agree to divide Europe between Germany and the Soviet Union. Finland, Estonia, Latvia, eastern Poland and Bessarabia (today Moldova), and the northeast province of Romania are to go to the Soviet Union; Lithuania and western Poland are to belong to Germany.

September 1, 1939. Germany invades Poland. Norway, Finland, Sweden, Spain and Ireland declare their neutrality. Later in September U.S. President Franklin Roosevelt announces that the U.S. will also remain neutral in the war.

September 3, 1939. The United Kingdom, France, New Zealand and Australia declare war on Germany.

September 17, 1939. The Soviet Union invades Poland and then occupies eastern Polish territories.

September 28-29, 1939. Poland surrenders to Germany.

October 11, 1939. Manhattan Project. U.S. President Franklin D. Roosevelt is presented a letter signed by Albert Einstein, urging the United States to rapidly develop the atomic bomb.

November 30, 1939. Soviet forces of over a million troops attack Finland and reach the Mannerheim Line, starting the war with Finland.