Date Explanation Your Reason
1939, September 1
The Invasion of Poland begins at 4:30 a.m. with the German Luftwaffe attacking several targets in Poland.
1939, September 1
The United Kingdom and France demand Germany's immediate withdrawal.
1939, September 10
Canada declares war on Germany.
1939, September 28
The Polish capital Warsaw surrender to the Germans.
1939, October 19
Portions of Poland are formally inducted into Germany
1939, October 19
The first Jewish ghetto is established at Lublin.
1939, November 8
An attempt to assassinate Hitler with a bomb while he makes a speech fails
1939, November 8
Germans appoint Hans Frank Governor General of Poland and begin accelerating the anti-Jewish programs there.
1939, December 18
The first Canadian troops arrive in Europe.
1939, December 28
Meat rationing program begins in Britain.
1940, January 1
Conscription extended in Britain, all men between 20 and 27 now liable.
1940, January 8
Bacon, butter, and sugar rationing begins in Britain.
1940, January 11
Meat rationing begins in France.
1940, March 12
Finland signs a peace treaty with the Soviet Union.
1940, March 16
German air raid on Scapa Flow causes first British civilian casualties.
1940, March 18
Mussolini agrees with Hitler that Italy will enter the war "at an opportune moment".
1940, March 28
Britain and France make a formal agreement that neither country will seek a separate peace with Germany.
1940, April 3
Churchill is appointed chairman of the Ministerial Defense Committee following the resignation of Lord Chatfield.
1940, April 9
Germany invades Denmark and Norway; Denmark surrenders.
1940, May 9
Conscription in Britain extended to age 36.
1940, May 10
Germany invades Belgium, France, Luxembourg and the Netherlands
1940, May 10
Winston Churchill becomes Prime Minister of the United Kingdom upon the resignation of Neville Chamberlain.
1940, May 11
1940, May 28
Belgium surrenders; Germans evacuate Narvik
1940, June 10
Italy declares war on France and the United Kingdom, Norway surrenders.
1940, June 14
Paris occupied by German troops; French government moves again, this time to Bordeaux.
1940, June 25
France officially surrenders to Germany at 0,35.
1940, June 30
Germany invades the Channel Islands.
1940, July 1
Channel Islands occupied by German forces; French government moves to Vichy.
1940, July 10
Battle of Britain begins.
1940, July 25
All women and children are ordered to evacuate Gibraltar.
1940, August 25
First British air raid on Berlin.
1940, September 13
Italy invades Egypt.
1940, September 27
The Tripartite Pact is signed by Japan, Germany and Italy.
1940, October 7
Germany invades Romania to restrain the Romanian Army.
1940, October 16
Draft registration begins in the United States.
1940, November 20
Hungary signs the Tripartite Pact.
1940, November 23
Romania signs the Tripartite Pact.
1940, November 24
Slovakia signs the Tripartite Pact
1941, March 1
Bulgaria signs the Tripartite Pact thus joining the Axis powers.
1941, March 25
Yugoslavia signs the Tripartite Pact.
1941, April 13
Japan and the Soviet Union sign a neutrality pact.
1941, May 9
United Kingdom takes control of Iraq and are reinforced by the arrival of 21st Indian Division at Basra; The German submarine U-110 is captured by the British Royal Navy. On board is the latest Enigma cryptography machine which Allied cryptographers later
1941, June 22
Germany invades the Soviet Union in Operation Barbarossa.
1941, June 23
Hungary and Slovakia declare war on the Soviet Union.
1941, June 26
Finland declares war on the Soviet Union.
1941, June 28
Albania declares war on the Soviet Union.
1941, July 4
Mass murder of Polish scientists and writers, committed by German troops in captured Polish city of Lwów.
1941, July 8
Yugoslavia dissolved by the Axis.
1941, July 12
Britain and Soviet Union sign mutual defence agreement, promising not to sign any form of separate peace agreement with Germany.
1941, July 13
Montenegro starts the first popular uprising in Europe against the Axis Powers.
1941, August 6
American and British governments warn Japan not to invade Thailand.
1941, August 9
Franklin D. Roosevelt and Winston Churchill meet at Argentia, Newfoundland. The Atlantic Charter is created as a result.
1941, August 18
Adolf Hitler orders a temporary halt to Nazi Germany's systematic euthanasia of mentally ill and handicapped due to protests. However, graduates of the T-4 Euthanasia Program were then transferred to concentration camps, where they continued in their trad
1941, September 4
The USS Greer becomes the first United States ship fired upon by a German submarine in the war, even though the United States is a neutral power. Tension heightens between the two nations as a result.
1941, September 6
The requirement to wear the Star of David with the word "Jew" inscribed, is extended to all Jews over the age of 6 in German-occupied areas.
1941, September 8
Siege of Leningrad begins - German forces begin a siege against the Soviet Union's second-largest city, Leningrad; Stalin orders the Volga Deutsche deported to Siberia.
1941, September 11
Franklin D. Roosevelt orders the United States Navy to shoot on sight if any ship or convoy is threatened.
1941, October 2
Operation Typhoon - Germany begins an all-out offensive against Moscow.
1941, October 17
The destroyer USS Kearney is torpedoed and damaged near Iceland, killing eleven sailors - the first American military casualties of the war.
1941, October 31
The destroyer USS Reuben James is torpedoed by a German U-boat near Iceland, killing more than 100 United States Navy sailors.
1941, November 12
Battle of Moscow - Temperatures around Moscow drop to -12 °C and the Soviet Union launches ski troops for the first time against the freezing German forces near the city.
1941, November 17
Joseph Grew, the United States ambassador to Japan, cables the State Department that Japan had plans to launch an attack against Pearl Harbor, Hawaii (his cable was ignored).
1941, November 26
Japanese attack fleet of 33 warships and auxiliary craft, including six aircraft carriers, sailed from northern Japan for the Hawaiian Islands; The Hull note ultimatum is delivered to Japan by the United States.
1941, November 27
Battle of Moscow - Germans reach their closest approach to Moscow. They are subsequently frozen by cold weather and attacks by the Soviets.
1941, December 5
The United Kingdom declares war on Finland, Hungary and Romania.
1941, December 7
Japanese aerial attack on Pearl Harbor and declares war on the United States and the United Kingdom. Air attacks also on Hong Kong, Singapore, Malaya, Thailand, the Philippines, and Shanghai.
1941, December 8
Japan invades Malaya; the United States and the United Kingdom declare war on Japan; The Netherlands declares war on Japan,
1941, December 9
China officially declares war on Japan 
1941, December 11
Germany and Italy declare war on the United States, United States reciprocates and declares war on Germany and Italy; US forces repel a Japanese landing attempt at Wake Island.
1941, December 12
The United States and the United Kingdom declare war on Romania and Bulgaria after they had declared war on both the United States and the United Kingdom; India declares war on Japan; United States seizes French ship Normandie.
1941, December 13
Hungary declares war on the United States and the United Kingdom, the United States and the United Kingdom reciprocate and declare war on Hungary.
1941, December 19
Hitler becomes Supreme Commander-in-Chief of the German Army
1942, January 20
Nazis at the Wannsee conference in Berlin decide that the "final solution to the Jewish problem" is relocation, and later extermination.
1942, January 26
The first American forces arrive in Europe landing in Northern Ireland.
1942, February 9
Top United States military leaders hold their first formal meeting to discuss American military strategy in the war.
1942, February 23
Japanese submarine I-17 fires sixteen high-explosive shells toward an oil refinery near Santa Barbara, California, causing little damage.
1942, April 3
Japanese forces begin an all-out assault on the United States and Filipino troops on the Bataan Peninsula. Bataan fell on April 9 and the Bataan Death "March" began.
1942, May 15
In the United States, a bill creating the Women's Auxiliary Army Corps (WAAC) is signed into law.
1942, June 1
Mexico declares war on Germany, Italy and Japan.
1942, June 4
The Battle of Midway; Reinhard Heydrich dies in Prague due to the assassination by Czechoslovak paratroopers (Operation Anthropoid)
1942, June 5
United States declares war on Bulgaria, Hungary and Romania.
1942, June 7
Japanese forces invade the Aleutian Islands. This is the first invasion of American soil in 128 years.
1942, June 12
Future essayist Anne Frank receives a diary for her thirteenth birthday.
1942, June 18
Manhattan Project started.
1942, July 9
Anne Frank's family goes into hiding in an attic above her father's office in an Amsterdam warehouse.
1942, July 18
The Germans test fly the Messerschmitt Me-262 using only its jets for the first time.
1942, July 22
The systematic deportation of Jews from the Warsaw Ghetto begins.
1942, August 22
Brazil declares war on the Axis countries.
1942, August 30
Luxembourg is formally annexed to the German Reich.
1942, September 1
Manhattan Engineering District is formally created, full-effort production of the atomic bomb is begun.
1942, September 1
Stalingrad is now completely encircled by German forces.
1942, October 3
First successful launch of A4-rocket from Test Stand VII at Peenemünde, Germany. The rocket flew 147 kilometres wide and reached a height of 84.5 kilometres and was therefore the first man-made object reaching space.
1942, October 22
Conscription age in Britain reduced to 18.
1942, November 19
Battle of Stalingrad - Soviet Union forces under General Georgy Zhukov launch the Operation Uranus counterattacks at Stalingrad, turning the tide of the battle in the USSR's favor.
1942, November 22
Battle of Stalingrad - The situation for the German attackers of Stalingrad seems desperate during the Soviet counter-attack Operation Uranus and General Friedrich Paulus sends Adolf Hitler a telegram saying that the German 6th army is surrounded.
1942, December 2
Below the bleachers of Stagg Field at the University of Chicago, a team led by Enrico Fermi initiate the first self-sustaining nuclear chain reaction (a coded message, "The Italian navigator has landed in the new world" was then sent to US President Frank
1942, December 4
In Warsaw, two Christian women, Zofia Kossak and Wanda Filipowicz risk their lives by setting up the Council for the Assistance of the Jews.
1943, January 18
Soviet officials announce they have broken the Wehrmacht's siege of Leningrad; The Jews in the Warsaw Ghetto rise up for the first time, starting the Warsaw Ghetto Uprising.
1943, January 27
50 bombers mount the first all American air raid against Germany (Wilhelmshaven was the target).
1943, February 2
In Russia, the Battle of Stalingrad comes to an end with the surrender of the German 6th Army.
1943, February 7
In the United States, it is announced that shoe rationing will go into effect in two days.
1943, February 11
General Eisenhower is selected to command the allied armies in Europe.
1943, April 7
Bolivia declares war on Germany, Japan and Italy.
1943, April 13
Radio Berlin announces the discovery by Wehrmacht of mass graves of Poles killed by Soviets in the Katyn massacre.
1943, July 12
The Wehrmacht and the Red Army fight the Battle of Prokhorovka - the greatest tank battle in history.
1943, July 19
Rome is bombed by the Allies for the first time in the war.
1943, July 22
Deportations of Jews from the Warsaw Ghetto begins. The extermination camp Treblinka is opened.
1943, July 24
Operation Gomorrah begins: British and Canadian aeroplanes bomb Hamburg by night, those of the Americans by day. By the end of the operation in November, 9,000 tons of explosives will have killed more than 30,000 people and destroyed 280,000 buildings.
1943, July 28
Operation Gomorrah - The British bomb Hamburg causing a firestorm that kills 42,000 German civilians.
1943, August 19
Roosevelt and Churchill sign the Quebec Agreement, formal agreement for coordinating atomic bomb research.
1943, September 3
Mainland Italy is invaded by Allied forces under Bernard L. Montgomery, for the first time in the war.
1943, September 8
United States General Dwight D. Eisenhower publicly announces the surrender of Italy to the Allies and the USAAF bombed the German General Headquarter for the Mediterranean zone Frascati bombing raid September 8, 1943; Julius Fucik is executed by Nazis.
1943, September 23
Italian Social Republic founded in German-occupied parts of Northern Italy.
1943, October 13
The new government of Italy sides with the Allies and declares war on Germany.
1943, October 18
Chiang Kai-shek took the oath of office as president of China.
1943, November 15
Allied Expeditionary Force for the invasion of Europe is officially formed; German SS leader Heinrich Himmler orders that Gypsies and "part-Gypsies" were to be put "on the same level as Jews and placed in concentration camps."
1943, November 22
US President Franklin D. Roosevelt, British Prime Minister Winston Churchill, and ROC leader Chiang Kai-Shek meet in Cairo, Egypt, to discuss ways to defeat Japan.
1943, December 3
Edward R. Murrow delivers his classic "Orchestrated Hell" broadcast over CBS Radio describing a Royal Air Force nighttime bombing raid on Berlin.
1943, December 24
US General Dwight D. Eisenhower becomes the Supreme Allied Commander in Europe.
1944, January 27
The two year Siege of Leningrad is lifted.
1944, June 5
Rome falls to the Allies. It is the first capital of an Axis nation to fall; More than 1000 British bombers drop 5000 tons of bombs on German gun batteries on the Normandy coast in preparation for D-Day.
1944, June 6
Battle of Normandy begins - Operation Overlord, code named D-Day, commences with the landing of 155,000 Allied troops on the beaches of Normandy in France. The allied soldiers quickly break through the Atlantic Wall and push inland in the largest amphibio
1944, June 13
Germany launches a V1 Flying Bomb attack on England.
1944, July 19
The entire Government of Japan resigns, Emperor Hirohito asks General Kuniaka Koiso to form a new government.
1944, July 24
Majdanek Concentration Camp is liberated by Soviet forces.
1944, August 15
Operation Dragoon begins with the amphibious Allied landings in southern France.
1944, August 19
French Resistance begins uprising in Paris.
1944, August 25
Paris is liberated; De Gaulle and Free French parade triumphantly down the Champs-Élysées.
1944, September 2
Allied troops enter Belgium.