January 1 - The world's longest railway line, the Siberian Railway (Transsibirskaya Magistral), is officially opened. The track was completed on July 21, 1904.
January 2 - Russian naval base Port Arthur surrenders to the Japanese.
January 19 - More than 215,000 miners strike in the Ruhr area of Germany.
January 22 - Blood Sunday: Soldiers shoot in front of the Winter Palace in St. Petersburg, led by priest Georgi Gapon. The beginning of the 1905 revolution.
January 24 - The Tsar orders the establishment of a military dictatorship in St. Petersburg to curb unrest.
January 27 - All major cities in Russia were on strike.
February 6 - Finnish State Councilor and Imperial Senate Prosecutor Eliel Soisalon-Soininen is assassinated. Lennart Hohenthal, using his disguise, broke into the prosecutor's apartment and shot him.
February 17 - Nicholas II's wire and St. Petersburg's governor, Grand Duke Sergei Alexandrovich, were bombed.
February 23 - The Battle of Mukden begins in the Russia-Japan War.
March 5 - Russia-Japan war: Russians begin a retreat after losing 100,000 men in three days.
March 23 - A riot broke out in Crete against the Ottoman regime. The uprising was led by Eleftherios Venizelos, an ally with Greece.
March 29 - In Finland, the implementation of the 1901 Conscription Act was suspended for the time being and replaced by financial compensation.
March 17 - Albert Einstein published a series of scientific articles on the photoelectric phenomenon that led to the birth of modern physics and the proof of atomic theory.
March 31 - The first crisis in Tangier: German Emperor Wilhelm II landed in Tangier, Morocco, to support the country against French imperialism and demanded uniform rights for Germany with France. French ally Russia has suffered losses in the war in Japan and internal unrest. France turned to Britain and demanded an international congress on the status of Morocco.
April 14 - Demonstration in Helsinki in favor of universal suffrage as the Senate discusses the extension of suffrage.
May 7 - Great persecution of Jews in Volyn, Belarus.
May 11 - Italy decides to join the racing equipment and build four battleships, four armored cruisers, 14 torpedo fighters, 12 submarines and 42 torpedo boats.
May 11 - Albert Einstein submitted his dissertation on Brown's movement for evaluation.
May 15 - Las Vegas is established in Nevada, USA.
May 27 - Russia-Japan War: The two-day naval battle of Tsushima begins. Admiral Togo of Japan destroyed the entire Russian Imperial Baltic Fleet in the Pacific.
May 27 - The Sointula communist settlement on Malkosaari in British Columbia, founded by Matti Kurika, finally disbanded.
June 7 - Norway announces that the alliance with Sweden is over.
June 19 - Pope Pius X allows Italian Catholics to participate in politics at his encyclical.
June 25 - Rebellion and street fighting in Łódź, Poland: 561 dead.
June 27 - Rebellion of the armored ship Potemkin in the Black Sea. The ship sailed to the rebel port of Odessa and surrendered to the Romanian authorities in Constanța in July.
June 30 - Albert Einstein published an article by Zur Elektrodynamik bewegter Körper in which he outlined a narrow theory of relativity.
July – September
July 2 - In France, a working day in the mines was set at nine hours.
July 3 - In France, the House of Representatives approves the separation of state and church by 509-44 votes.
July 21 - Worker activist Kalle Procopé shoots gendarmerie lieutenant Vladimir Kramarenko in Vyborg.
July 25 - Russian Emperor