October 1921

• Born: James Whitmore, US actor, in White Plains, New York[1] (died 2009)

• Georges Clemenceau, unveiling a war memorial in his home village, answers critics who have accused him of having sacrificed the rights of France to "the policy of alliances".[2]
• While on a voyage from Fairbanks, Alaska, to Tolovana with 21 crewmen but no passengers or cargo aboard, the US passenger ship a voyage in the Territory of Alaska from Fairbanks to Tolovana with 21 crewmen but no passengers or cargo aboard, the 495-gross register ton, the US149.6-foot (45.6 m) passenger ship Tanana, a sternwheel paddle steamer, hits a submerged snag on the Tanana River 1 mile (1.6 km) above Minto. While attempting to beach, it sinks in 6 feet (1.8 m) of water.[3]
• Born: Edmund Crispin (pseudonym of Robert Bruce Montgomery), British crime writer and composer (died 1978)[4]
• Died: King William II of Württemberg, 73, German ruler deposed in 1918[5]

• Died: Madeline Davis, 23, an inexperienced amateur stunt flier, during an attempt to become the first woman to transfer from a moving automobile to an airplane flying overhead via a rope ladder, at Long Branch, New Jersey, United States. Davis loses her grip on the ladder and hits the ground at a speed of about 45 miles per hour (72 kilometres per hour).[6][7]

• The first radio broadcast of a baseball World Series game is made by Pittsburgh station KDKA,[8] and also heard on a group of other commercial and amateur stations throughout the eastern United States.
• The Golden Moth, with lyrics by P. G. Wodehouse and music by Ivor Novello (his first complete score), opens at the Adelphi Theatre in London's West End, starring Bobbie Comber.[9]

• The first "Sweetest Day" takes place in Cleveland, Ohio, United States, organized by local confectioners.[10]
• The British passenger ship Rowan is rammed from astern by the US ship West Camak in fog in the North Channel. While passengers are mustered on deck, another UK ship, Clan Malcolm, rams the Rowan from starboard, causing it to sink with the loss of 22 of the 97 people on board.[11][12]

• Hungary's former Ferenc József Tudományegyetem ("Franz Josef University") is inaugurated following its move to Szeged.[13]
• The Cadle Tabernacle, a nondenominational, 10,000-seat auditorium in Indianapolis, United States, built by E. Howard Cadle, is dedicated by Rodney "Gipsy" Smith.[14]
• Australian cricket team in South Africa in 1921–22: The first Test match of the tour between Australia and South Africa, held in Durban, ends in a draw.[15]

• The Treaty of Kars is signed between the Grand National Assembly of Turkey and the Soviet Socialist Republics of Armenia, Azerbaijan and Georgia, establishing the boundaries between Turkey and the states of the south Caucasus.[16]
• Swedish Social Democratic party leader Hjalmar Branting becomes Prime Minister, after strong general election gains for his party.
• The New York Giants (NL) defeats New York Yankees (AL) to win the 1921 World Series by 5 games to 3.[17]
• Born: Yves Montand, French actor, in Monsummano Terme, Italy, as Ivo Livi.[18]

• Compañía Española de Tráfico Aéreo, based in Seville, launches the first air service between Spain and Morocco. The company would later become part of the Iberia airline.[19]

• Brazil's President Epitácio Pessoa addresses Congress on the subject of the crisis in the coffee industry and proposes new measures to protect Brazilian producers.[20]
• Born: George Mackay Brown, Scottish poet and author, in Stromness, Orkney (died 1996)[21]

• The Taurida Governorate is disestablished and the Crimean Autonomous Soviet Socialist Republic is created within the Russian Soviet Federative Socialist Republic.[22]
• Died: King Ludwig III of Bavaria, 76, German ruler deposed in 1918[23]

• "Bloody Night" ("Noite Sangrenta"): A revolt in Lisbon claims the lives of several politicians.[24]
• Born: Gunnar Nordahl, Swedish footballer and manager, in Hörnefors (died 1993)[25]
• Died: António Granjo, 39, Prime Minister of Portugal; António Machado Santos, 46, Portuguese naval officer and politician; and other politicians, all assassinated by monarchist rebels.[26]

• 1921 Tampa Bay hurricane: The hurricane forms from a trough in the southwestern Caribbean Sea.[27]
• US cargo ship Santa Rita departs New Orleans, Louisiana, for Italy. After being reported off Key West, Florida, it is presumed to have foundered in the Atlantic Ocean with the loss of all hands.[28]

• Shortly after the start of the peace conference between Ireland and the United Kingdom in London, the German police, tipped off by a British liaison officer, discover a ship laden with weapons in the port of Hamburg, bound for Ireland.[29]
• George Melford's silent film The Sheik, based on the novel by Edith Maude Hull and starring Rudolph Valentino, receives its première in Los Angeles, United States.[30]
• Born:
  • Malcolm Arnold, English composer, in Northampton (died 2006)[31]
  • Mohammad Mohammadullah, President of Bangladesh, in Raipur, India (died 1999)[32]

• Ireland and England draw 1–1 at football in the 1921–22 British Home Championship opening match at Windsor Park, Belfast.[33]

• Chester W. Taylor is elected as a U.S. Representative from Arkansas, in place of his father, Samuel Mitchell Taylor, who had died a month earlier.[34]
• Engineer Hugo Abt files a patent in the US for a new design of bascule bridge.[35]

Died: Bat Masterson, 67, US gunfighter and journalist, of a heart attack while working at his desk on a column for the Morning Telegraph[36]

• The Chicago Theatre, the oldest surviving grand movie palace in the United States, opens with The Sign on the Door, starring Norma Talmadge and Lew Cody.[37]

• Died: Yan Fu, 67, Chinese scholar and translator[38]

• The first ever gubernatorial recall election is held in North Dakota, United States, after the incumbent, Lynn Frazier, is blamed for an economic depression in the agricultural sector.[39] He is replaced the following month by Ragnvald A. Nestos.

• Construction of the Link River Dam, a stage in the Klamath Project in Oregon, United States, is completed.[40]
• Centre College's American football team, led by quarterback Bo McMillin, defeats Harvard University 6–0 to break Harvard's five-year winning streak; the match becomes known as "football's upset of the century".[41]

• The 1921 South American Championship football tournament ends in victory for Argentina.[42]