Sinking of HMS Courageous, 17 September 1939 (public domain via WW2 Database)

80 Years Ago—September 17, 1939: Soviet troops (allied with Germany) invade Poland, surrounding Polish troops.

150 Polish military and civilian planes fly to Romania; pilots will make way to Britain to fight again.

Off the Irish coast, U-boat U-29 sinks British aircraft carrier HMS Courageous, 518 killed.

US C-47 Skytrains towing Waco CG-4 gliders over Bergeijk, Holland en route the Operation Market Garden landings near Eindhoven, 17 September 1944 (US National Archives)

75 Years Ago—Sept. 17, 1944: Operation Market Garden begins: 20,000 US and British paratroopers land in Nijmegen, Eindhoven, and Arnhem in the Netherlands, with a British ground offensive designed to link with the airborne units.

In Italy, US Fifth Army breaks the German Gothic Line at Il Giogo Pass.

German Army horses towing an infantry gun, Poland, September 1939 (German Federal Archive, Bild 183-S54817)

80 Years Ago—September 16, 1939: In Poland, Germans take Brest-Litovsk and surround Warsaw.

First German U-boat attack on an Allied North Atlantic convoy; U-31 sinks British freighter Aviemore in convoy OB-4 off Land’s End.

75 Years Ago—Sept. 16, 1944: Soviets launch assault toward Gulf of Riga on the Baltic.

US Marines on Orange Beach on Peleliu, 15 September 1944 (US Marine Corps)

80 Years Ago—September 15, 1939: Aviator Charles Lindbergh makes his first radio broadcast opposing US involvement in the war.

African-American Marines on Peleliu, 15 September 1944 (US National Archives)

75 Years Ago—Sept. 15, 1944: US Marine 1^st Division land on Peleliu in the Palau Islands in the Pacific.

Allied forces from Operation Dragoon (landings in southern France) are transferred from the Mediterranean Theater of Operations (MTO) to the European Theater of Operations (ETO).

T/Sgt. Joe Trdenic of US 36th Infantry Division receives gift from 11-year-old Therese Grenier in Luxeuil, France, 16 Sept 1944 (US Army Center of Military History)

80 Years Ago—September 14, 1939: Off the Hebrides, German submarine U-39 attacks carrier HMS Ark Royal but misses and is sunk by British destroyers Faulknor, Foxhound, and Firedrake, the first U-boat sunk in WWII.

Germans take Gdynia, the only remaining Polish port.

75 Years Ago—Sept. 14, 1944: Operation Dragoon, the Allied “Champagne Campaign” in southern France, concludes: 131,000 German POWs have been taken, 40% of Army Group G.

Mutiny trial begins for 50 Port Chicago sailors at Treasure Island, CA (Read more: “The Port Chicago Disaster—The Mutiny Trial”).

Great Atlantic Hurricane kills 390 from North Carolina to New England, and sinks 2 US Coast Guard cutters.

German Ju-87 Stukas over Poland, September 1939 (German Federal Archives, Bild 183-1987-1210-502)

80 Years Ago—September 13, 1939: Germans resume offensive on Warsaw, Poland.

Stained glass in Notre Dame Cathedral in Paris is removed for safekeeping.

British civilians are allowed to carry torches (flashlights) in blackout if screened with tissue paper.

Leopold Canal, Belgium (Library and Archives Canada)

75 Years Ago—Sept. 13, 1944: In Belgium, Canadians cross Leopold Canal and Canal de Derivation, while British cross Meuse-Escaut Canal.

Gov. Gen. of Canada Alexander Cambridge, Franklin Roosevelt, Winston Churchill, and Canadian Prime Minister Mackenzie King at the Octagon Conference in Quebec, 12 September 1944 (Library and Archives, Canada)

80 Years Ago—September 12, 1939: Anglo-French Supreme War Council agrees to postpone military operations.

75 Years Ago—Sept. 12, 1944: Romania signs an armistice with the Allies and agrees to fight Germany.

First German city falls to the Allies as the US First Army takes Roetgen.

In Normandy, Canadians take crucial port of Le Havre; due to damage, the port won’t open for four weeks.

Ships of US Task Force 38 strike Cebu in the Philippines, sinking over 40 Japanese ships.

Octagon Conference begins in Québec between US, UK, and Canada.

Map of the Allied campaign in Northwest Europe, 26 Aug.-14 Sept. 1944 (US Military Academy)

80 Years Ago—September 11, 1939: Polish submarines are ordered to break through to Britain or to be interned in Sweden; many will fight for the Allies.

“Lord Haw Haw” (US-born British subject William Joyce) begins broadcasting anti-British propaganda to Britain on “Germany Calling” radio show on Radio Hamburg.

75 Years Ago—Sept. 11, 1944: US First Army reaches the Siegfried Line at the German border and crosses into Germany north of Trier.

At Saulieu, France, official contact is made between Overlord forces (landed in Normandy 6/6/44) and Dragoon forces (landed in southern France 8/15/44); Allied front now runs from the English Channel to the Swiss border to the Mediterranean.

Canadian recruiting poster, WWII

80 Years Ago—September 10, 1939: Canada declares war on Germany.

The Battle of the Atlantic officially begins; this naval battle between the Allies and the Axis will last until V-E Day.

US troops carrying supplies on the Gothic Line (US Army Center of Military History)

75 Years Ago—Sept. 10, 1944: US First Army liberates Luxembourg.

In Italy, US Fifth Army launches offensive toward Bologna on the German “Gothic Line.”

German troops in a Polish town, September 1939 (German Federal Archive, Bild 101I-012-0037-23A)

80 Years Ago—September 9, 1939: Battle of Bzura (Kutno): Polish Army makes sole offensive of war, forcing Germans to withdraw from Warsaw.

First troops of British Expeditionary Force sail in convoy to France.

Surprise sneak preview of Gone with the Wind is held at the Fox Theater in Riverside, CA; producer David O. Selznick gauges the audience reaction.

Coldstream Guards, British Expeditionary Force landing at Cherbourg, France, Sept.-Oct. 1939. (Imperial War Museum)

75 Years Ago—Sept. 9, 1944: Canadians overrun German rocket bases on the Belgian coast.

US First Army enters the Netherlands near Maastricht.

Near Brest, France, four men of the US 2^nd Ranger Battalion, led by Lt. Robert Edlin, with lots of bluffing and bravado, take Batterie Graf Spee at Locrist without firing a shot—and take 814 POWs.

Girl holding her dog in devastated Warsaw, Poland, 5 September 1939 (US Holocaust Museum)

80 Years Ago—September 8, 1939: German troops reach Warsaw suburbs; Polish government evacuates to Lublin.

President Franklin D. Roosevelt declares a limited state of emergency and orders an increase in the armed forces.

Koch Karadzhev (foreground) and others welcome Soviet troops into Bulgaria, Sep 1944 (public domain via WW2 Database)

75 Years Ago—Sept. 8, 1944: Soviet troops enter Bulgaria, which switched sides and declared war on Germany the day before.

First German V-2 rocket hits London.

V-2 Rocket launch, Peenemünde, Germany, 21 June 1943 (German Federal Archive: Bild 141-1880)