Year 1915 (MCMXV) was a common year starting on Friday of the Gregorian calendar.
January
While working as a cook at New York's Sloan Hospital under an assumed name, Typhoid Mary infects 25 people, and is placed in quarantine for life.
January 1: World War I, The battleship HMS Formidable is sunk off Lyme Regis, Dorset, England, by a German U-Boat.
January 12: The United States House of Representatives rejects a proposal to give women the right to vote.
January 13: An earthquake (6.8 in Richter scale) in Avezzano, Italy, kills more than 29,000.
January 19: Georges Claude patents the neon discharge tube for use in advertising.
January 19: German zeppelins bomb the cities of Great Yarmouth and King's Lynn in the United Kingdom for the first time, killing more than 20.
January 31: World War I, Germany uses poison gas against the Russians.
January 31: A symbolic looking formation is seen upon the moon - six or seven white spots, in Littrow, arranged like the Greek letter 'Gamma'.
(Books519)
February
February 8: The controversial film, The Birth of a Nation, directed by D.W. Griffith, premieres in Los Angeles, California.
February 12: In Washington, D.C. the first stone of the Lincoln Memorial is put into place.
February 13: Steep Island, Chusan Archipelago - a lighthouse keeper complained to the Royal Navey that a British warship had fired upon him, but, no vessel had fired
a shot. (Books519)
February 14: Objects with "powerful searchlights" are seen passing over the St. Lawrence River near Morristown, New York. Aeroplanes are blamed, then
fire-balloons and then paper balloons. (Books519)
March
March to October: The 1915 locust plague breaks out in Palestine.
March 3: NACA, the predecessor of NASA, is founded.
March 18: World War I, A British attack on the Dardanelles fails.
March 19: Pluto is photographed for the first time but is not then classified as a planet.
March 25: The U.S. submarine F-4 sinks off Hawaii; 21 are killed.
April
April 24: Onset of the Armenian Genocide.
May
May 5: World War I. The Turks begin shelling Anzac Cove from a new position behind their lines.
May 7: World War I. The RMS Lusitania is sunk by a German U-boat, killing 1,198.
May 17: The last purely Liberal government in the United Kingdom ends when Prime Minister Herbert Henry Asquith forms an all party coalition.
May 22: The Quintinshill railway disaster in Scotland leaves more than 200 dead.
May 23: World War I. Italy joins the Allies after they declare war on Austria-Hungary.
June
June 3: Mexican Revolution. Troops of Obregon and Villa clash at León: Obregon loses his right arm in grenade attack but Villa is decisively defeated.
June 9: U.S. Secretary of State William Jennings Bryan resigns over a disagreement regarding his nation's handling of the RMS Lusitania sinking.
June 16: The British Women's Institute is founded.
June 22: A fall of hailstones the size of baseballs fall in Maryland, USA. (Books177)
July
July 7: An extremely overloaded Great Gorge and International Railway trolley with 157 passengers crashes near Queenston, Ontario, resulting in 15
casualties.
July 24: The steamer Eastland capsizes in central Chicago, with the loss of 844 lives.
July 28: The United States occupation of Haiti begins.
August
August 5-23: Hurricane Two of the 1915 Atlantic hurricane season over Galveston and New Orleans leaves 275 dead.
August 6: World War I. Battle of Sari Bair - The Allies mount a diversionary attack timed to coincide with a major Allied landing of reinforcements at Suvla
Bay.
August 16: The Entente promises the Kingdom of Serbia, should victory be achieved over Austro-Hungary and its allied Central Powers, the territories of Baranja, Srem
and Slavonia from the Cisleithanian part of the Dual Monarchy; Bosnia and Herzegovina; and eastern Dalmatia (from the river of Krka to Bar).
August 17: Jewish American Leo Frank is lynched for the alleged murder of a 13-year-old girl in Atlanta, Georgia.
September
September 6: The first prototype tank is tested for the British Army for the first time.
September 11: The Pennsylvania Railroad begins electrified commuter rail service between Paoli and Philadelphia, Pennsylvania, using overhead AC trolley wires for
power.
October
October 5-29: An enormous fall of a white web like substance across thousands of square miles in Australia. (Books537)
October 12: World War I. British nurse Edith Cavell is executed by a German firing squad for helping Allied soldiers escape from Belgium.
October 15: World War I. Austria-Hungary invades the Kingdom of Serbia. Bulgaria enters the war, invading Kingdom of Serbia.
October 19: Mexican Revolution. The U.S. recognizes the Mexican government of Venustiano Carranza de facto (not de jure until 1917).
November
Sykes-Picot Agreement: The governments of Britain and France secretly agree to overtake the Middle-Eastern regions of the Ottoman Empire and establish their own
zones of influence.
November 25: The theory of general relativity is formulated.
December
December 11: A "particularly bright spot upon the moon" is observed on the north shore of the Mare Crisium and "looked almost like a star."
(Books520)
December 25: British and German forces get out of the trenches in World War I and have a free-for-all kick-around football game in no-man's land.