January 8 – The Blackstone Library is dedicated, marking the beginning of the Chicago Public Library system
January 18 – The Herero Rebellion in German South-West Africa begins
January 23 – The Ålesund Fire destroys most buildings in the town of Ålesund, Norway, leaving about 10,000 people without shelter
February 7 – The Great Baltimore Fire in Baltimore, Maryland, destroys over 1,500 buildings in 30 hours
February 8–9 – A surprise Japanese naval attack on Port Arthur (Lüshun) in Manchuria starts the Russo-Japanese War
March 31 – British expedition to Tibet – Battle of Guru- British troops under Colonel Francis Younghusband defeat ill-equipped Tibetan troops
April 19 – The Great Toronto Fire destroys much of that city’s downtown, but there are no fatalities.
April 30 – The Louisiana Purchase Exposition World’s Fair opens in St. Louis, Missouri
July 1 – The third Modern Olympic Games opens in St. Louis, Missouri, United States as part of the World’s Fair
August 11 – Battle of Waterberg- Lothar von Trotha defeats the Herero people in German South-West Africa, and drives them into the Omaheke desert, starting the Herero and Namaqua Genocide
October 21 – The Russian Baltic Fleet fires on British trawlers it mistakes for Japanese torpedo boats, in the North Sea.
November 8 – U.S. presidential election, 1904- Republican incumbent Theodore Roosevelt defeats Democrat Alton B. Parker.