WHAT ALL HAPPENED APRIL TO DECEMBER 1915
Find out what all happened April to December 1915

Militia officer Henry Pedris executed by firing squad at Colombo, Ceylon - an act widely regarded as a miscarriage of justice by the British colonial authorities. (7. July 1915)

US Navy salvage divers raise F-4, the first U.S. submarine sunk in an accident. (29. August 1915)

World War I: end of First Battle of the Isonzo. (7. July 1915)

World War I: The German 12th Army occupies Warsaw during the Gorlice–Tarnów Offensive and the Great Retreat of 1915. (4. August 1915)

World War I: The Battle of Gallipoli begins—The invasion of the Turkish Gallipoli Peninsula by Australian, British, French and New Zealand troops begins with landings at Anzac Cove and Cape Helles. (25. April 1915)

World War I: Italy declares war on Austria-Hungary. (24. May 1915)

William Jennings Bryan resigns as Woodrow Wilson's Secretary of State over a disagreement regarding the United States' handling of the sinking of the RMS Lusitania. (9. June 1915)

Parris Island is officially designated a United States Marine Corps Recruit Depot. (1. November 1915)

Lassen Peak erupts with a powerful force, and is the only mountain other than Mount St. Helens to erupt in the contiguous US during the 20th century. (22. May 1915)

World War I: The Kingdom of Bulgaria joins the Central Powers. (14. October 1915)

The last British Liberal Party government (led by Herbert Henry Asquith) falls. (17. May 1915)

The Battle for the Hohenzollern Redoubt marks the end of the Battle of Loos in northern France, World War I. (13. October 1915)

The pacifist Zimmerwald Conference begins. (5. September 1915)

World War I: German submarine U-20 sinks RMS Lusitania, killing 1,198 people including 128 Americans. Public reaction to the sinking turns many formerly pro-Germans in the United States against the German Empire (7. May 1915)

World War I: The Second Battle of Champagne begins. (25. September 1915)

A Category 4 hurricane hits Galveston, Texas with winds at 135 miles per hour (217 km/h). (17. August 1915)

Denmark amends its constitution to allow women's suffrage. (5. June 1915)

RFC Captain Lanoe Hawker becomes the first British military aviator to earn the Victoria Cross, for defeating three German two-seat observation aircraft in one day, over the Western Front. (25. July 1915)

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. (6. August 1915)

Three trains collide in the Quintinshill rail disaster near Gretna Green, Scotland, killing 227 people and injuring 246; the accident is found to be the result of non-standard operating practices during a shift change at a busy junction. (22. May 1915)