|Wikimedia Commons has media related to 1905.|
1905 (MCMV)was a common year starting on Sunday of the Gregorian calendar and a common year starting on Saturday of the Julian calendar, the 1905th year of the Common Era (CE) and Anno Domini (AD) designations, the 905th year of the 2nd millennium, the 5th year of the 20th century, and the 6th year of the 1900s decade. As of the start of 1905, the Gregorian calendar was 13 days ahead of the Julian calendar, which remained in localized use until 1923.
As the second year of the massive Russo-Japanese War began, more than 100,000 died in the largest world battles of that era, and the war chaos lead to a revolution against the Tsar (Shostakovich's 11th Symphony is subtitled The Year 1905 to commemorate this). Canada and the U.S. expanded west, with the Alberta and Saskatchewan provinces and the founding of Las Vegas. 1905 is also the annus mirabilis of Albert Einstein, who published papers which laid the foundations for quantum physics, introduced the special theory of relativity, explained Brownian motion, and established mass–energy equivalence.
- February 12 – In Christchurch, New Zealand, the Cathedral of the Blessed Sacrament is opened.
- February 16 – At Haulbowline Base in Ireland, two explosions on board HM Submarine A5, due to gasoline fumes after refueling, kill six of eleven crew members.
- February 17 – At Fremantle, Australia, the RMS Orizaba is wrecked, but all 160 passengers and the mail are saved.
- February 20 – Russo-Japanese War: The Battle of Mukden begins in Manchuria.
- February 23 – Rotary International is founded, in Chicago, Illinois.
- March 1 – Australian Conservative leader Richard Butler takes office, as Premier of South Australia.
- March 3 – Tsar Nicholas II of Russia agrees to create an elected assembly (the Duma).
- March 4 – Theodore Roosevelt is sworn in for a full term, as President of the United States.
- March 5 – Russo-Japanese War: Russian troops begin to retreat from Mukden, after losing 100,000 troops in 3 days.
- March 10
- March 13 – Mata Hari introduces her exotic dance act in Paris.
- March 17 – Albert Einstein publishes his paper "On a heuristic viewpoint concerning the production and transformation of light", in which he explains the photoelectric effect, using the notion of light quanta.
- March 20 – Grover Shoe Factory disaster: A boiler explosion, building collapse and fire in Brockton, Massachusetts, kills 58.
- March 23 – Theriso revolt: About 1,500 men, led by Eleftherios Venizelos, meet at the village of Theriso, Crete, to challenge the island's authoritarian government, and press for its unification with Greece.
- March 31 – Wilhelm II, German Emperor asserts German equality with France in Morocco, triggering the Tangier or First Moroccan Crisis.
- April – Albert Einstein works on the special theory of relativity, as well as the theory of Brownian motion.
- April 1 – The Penny Post is established, between the United Kingdom and Australia.
- April 2 – The Simplon Tunnel is officially opened, through the Alps.
- April 3 – Boca Junior, a well known football club of Argentina, is founded in Buenos Aires.
- April 4 – In India, the 1905 Kangra earthquake hits the Kangra Valley, kills 20,000, and destroys most buildings in Kangra, McLeod Ganj and Dharamshala.
- April 6 – Lochner v. New York: The Supreme Court of the United States invalidates New York's 8-hour-day law.
- April 14 – Erik Gustaf Boström resigns as the Prime Minister of Sweden, over the issue of the Swedish-Norwegian Union; his Minister without Portfolio, Johan Ramstedt, becomes the new Prime Minister of Sweden.
: Las Vegas
is founded with auction of 110 acres (0.45 km2
- October – Fauvist artists, led by Henri Matisse and André Derain, first exhibit their works, at the Salon d'Automne in Paris.
- October 1 – A Czech worker, František Pavlík (1885–1905), was bayoneted to death during a demonstration for a Czech university in Brno. This event was the motivation for a piano sonata, 1. X. 1905, by composer Leoš Janáček, which premiered on 27 January 1906.
- October 2 – HMS Dreadnought is laid down in the United Kingdom, revolutionizing battleship design and triggering a naval arms race.
- October 5 – The Wright brothers' third aeroplane (Wright Flyer III) stays in the air for 39 minutes with Wilbur piloting, the first aeroplane flight lasting over half an hour.
- October 16 – The Partition of Bengal is made by Lord Curzon, to separate the region of Bengal by Muslim and Hindu territories, until its reunification in 1911.
- October 20 – Galatasaray S.K. sports and Association football club is founded in Istanbul.
- October 26 – Sweden agrees to the repeal of the union with Norway.
- October 29
- October 30
- November 4 – The application of the infamous February Manifesto, removing the veto of the Diet of the autonomous Grand Principality of Finland over matters considered by the Emperor to concern Russian imperial interests, is interrupted by the new November Manifesto. The Senate of Finland is ordered to put forward a proposal for parliamentary reform, based on unicameralism, and universal and equal suffrage.
- November 7 – Lawyer and liberal politician Karl Staaff becomes Prime Minister of Sweden, after a Riksdag election based mainly on voting rights reform.
- November 9 – The Province of Alberta, Canada, holds its first general election.
- November 12 – Norway holds a referendum, resulting in popular approval of the Storting's decision to authorise the government to make the offer of the throne of the newly-independent country.
- November 17 – The Japan–Korea Treaty of 1905 ("Eulsa Treaty") effectively makes Korea a protectorate of Japan.
- November 18 – Prince Carl of Denmark becomes King Haakon VII of Norway.
- November 28 – Irish nationalist Arthur Griffith founds Sinn Féin in Dublin, as a political party whose goal is independence for all of Ireland.
- November–December – Russian Revolution of 1905: In the Baltic governorates, workers and peasants burn and loot hundreds of Baltic German manors. The Imperial Russian Army thereafter executes and deports thousands of looters.