WHAT ALL HAPPENED JUNE TO DECEMBER 1939
Find out what all happened June to December 1939

Siam is renamed Thailand by Plaek Pibulsonggram, the country's third prime minister. (24. June 1939)

World War II: Germany and the Soviet Union sign a non-aggression treaty, the Molotov-Ribbentrop Pact. In a secret addition to the pact, the Baltic states, Finland, Romania, and Poland are divided between the two nations. (23. August 1939)

Winter War: Finland holds off a Soviet attack in the Battle of Kelja. (27. December 1939)

World War II: following the start of the invasion of Poland the previous day, the Free City of Danzig (now Gdańsk, Poland) is annexed by Nazi Germany. (2. September 1939)

World War II: South Africa declares war on Germany. (6. September 1939)

World War II: Germany's invasion of Poland ends with the surrender of Polesia army after the Battle of Kock (6. October 1939)

General George C. Marshall becomes Chief of Staff of the United States Army. (1. September 1939)

The Baseball Hall of Fame opens in Cooperstown, New York. (12. June 1939)

World War II: First attack on British territory by the German Luftwaffe. (16. October 1939)

World War II: Sonderaktion Krakau takes place. (6. November 1939)

In Washington, D.C., US President Franklin D. Roosevelt lays the cornerstone of the Jefferson Memorial. (15. November 1939)

HMS Duchess sinks after a collision with HMS Barham off the coast of Scotland with the loss of 124 men. (12. December 1939)

World War II: Battle of the River Plate – The Admiral Graf Spee is scuttled by Captain Hans Langsdorff outside Montevideo. (17. December 1939)

World War II: a Bristol Blenheim is the first British aircraft to cross the German coast following the declaration of war and German ships are bombed. (4. September 1939)

The Japanese Mitsubishi G4M twin-engine "Betty" Bomber makes its maiden flight. (23. October 1939)

Huỳnh Phú Sổ founds Hòa Hảo Buddhism. (4. July 1939)

Nazi Germany and the Soviet Union agree on a division of Poland after their invasion during World War II. (28. September 1939)

World War II: U.S. President Franklin D. Roosevelt orders the United States Customs Service to implement the Neutrality Act of 1939, allowing cash-and-carry purchases of weapons by belligerents. (4. November 1939)

Albert Einstein and Leó Szilárd write a letter to Franklin D. Roosevelt, urging him to begin the Manhattan Project to develop a nuclear weapon. (2. August 1939)

Judge Joseph Force Crater, known as the "Missingest Man in New York", is declared legally dead. (6. June 1939)