in Terezin, Austria-Hungary, after three years in prison. April 30 – WWI: The Second Transjordan attack on Shunet Nimrin and Es Salt, launched by units of the Egyptian Expeditionary Force, ends on 4 May, with their withdrawal back to the Jordan Valley. May May 1 – WWI: German troops enter Don Host Oblast; they capture Rostov-on-Don on May 8. May 2 – General Motors acquires the Chevrolet Motor Company of Delaware. May 7 – WWI: The British capture Kirkuk. May 9 – WWI – Second Ostend Raid: The British Royal Navy unsuccessfully attempts, for a second time, to seal off the German U-boat base here. May 11 – The Mountainous Republic of the Northern Caucasus is officially established. May 14 – The Three Minute Pause, initiated by the daily firing of the Noon Gun on Signal Hill, is instituted by Cape Town Mayor Sir Harry Hands. It will inspire the introduction of the two-minute silence in November 1919. May 15 The Finnish Civil War ends. The United States Post Office Department begins the world's third regular airmail service, between New York City, Philadelphia and Washington, D.C. May 16 – The Sedition Act of 1918 is approved by the U.S. Congress. May 20 – The small town of Codell, Kansas is hit for the third year in a row, on the same date, by a tornado. May 21 – The United States Army Aviation Section is separated from the Signal Corps, and divided into the Division of Military Aeronautics and the Bureau of Aircraft Production. May 24 – Women in Canada, excluding residents of Quebec, are granted the right to vote in federal elections. May 26 – The Transcaucasian Democratic Federative Republic is abolished; Georgia declares its independence as the Democratic Republic of Georgia. May 27 – WWI: The Third Battle of the Aisne commences. May 28 – Armenia and Azerbaijan declare their independence as the First Republic of Armenia and the Azerbaijan Democratic Republic respectively. May 29 – WWI: The week-long Battle of Sardarabad concludes with defending Armenian forces victorious over the Ottomans. May 29–30 – WWI: Battle of Skra di Legen – The Greek National Defence Army Corps defeats the Bulgarians. June June–August – The "Spanish flu" becomes pandemic. Over 30 million people die in the following 6 months. June 1 – WWI: The Battle of Belleau Wood begins. June 4 – RMS Kenilworth Castle, one of the Union-Castle