| 123871 | October 30 | Event | 1938 – Orson Welles broadcasts his radio play of H. G. Wells's The War of the Worlds, causing anxiety in some of the audience in the United States. |
| 123872 | October 30 | Event | 1941 – World War II: Franklin D. Roosevelt approves U.S. $1 billion in Lend-Lease aid to the Allied nations. |
| 123873 | October 30 | Event | 1941 – One thousand five hundred Jews from Pidhaytsi (in western Ukraine) are sent by Nazis to Bełżec extermination camp. |
| 123874 | October 30 | Event | 1942 – Lt. Tony Fasson, Able Seaman Colin Grazier and canteen assistant Tommy Brown from HMS Petard board U-559, retrieving material which would lead to the decryption of the German Enigma code. |
| 123875 | October 30 | Event | 1944 – Anne and Margot Frank are deported from Auschwitz to the Bergen-Belsen concentration camp, where they die from disease the following year, shortly before the end of WWII. |
| 123876 | October 30 | Event | 1945 – Jackie Robinson of the Kansas City Monarchs signs a contract for the Brooklyn Dodgers to break the baseball color line. |
| 123877 | October 30 | Event | 1947 – The General Agreement on Tariffs and Trade (GATT), which is the foundation of the World Trade Organisation (WTO), is founded. |
| 123878 | October 30 | Event | 1950 – Pope Pius XII witnesses the "Miracle of the Sun" while at the Vatican. |
| 123879 | October 30 | Event | 1953 – Cold War: U.S. President Dwight D. Eisenhower formally approves the top secret document National Security Council Paper No. 162/2, which states that the United States' arsenal of nuclear weapons must be maintained and expanded to counter the commun |
| 123880 | October 30 | Event | 1960 – Michael Woodruff performs the first successful kidney transplant in the United Kingdom at the Edinburgh Royal Infirmary. |
| 123881 | October 30 | Event | 1961 – Nuclear testing: The Soviet Union detonates the hydrogen bomb Tsar Bomba over Novaya Zemlya at 50 megatons of yield, it remains the largest explosive device ever detonated, nuclear or otherwise. |
| 123882 | October 30 | Event | 1961 – Because of "violations of Vladimir Lenin's precepts", it is decreed that Joseph Stalin's body be removed from its place of honour inside Lenin's tomb and buried near the Kremlin Wall with a plain granite marker instead. |
| 123883 | October 30 | Event | 1965 – English model Jean Shrimpton causes a global sensation by wearing a daring white minidress to Derby Day at Flemington Racecourse in Melbourne, Australia. |
| 123884 | October 30 | Event | 1965 – Vietnam War: Near Da Nang, United States Marines repel an intense attack by Viet Cong forces, killing 56 guerrillas. |
| 123885 | October 30 | Event | 1970 – In Vietnam, the worst monsoon to hit the area in six years causes severe floods, kills 293, leaves 200,000 homeless and virtually halts the Vietnam War. |
| 123886 | October 30 | Event | 1972 – A collision between two commuter trains in Chicago kills 45 and injures 332. |
| 123887 | October 30 | Event | 1973 – The Bosphorus Bridge in Istanbul, Turkey is completed, connecting the continents of Europe and Asia over the Bosphorus for the second time. |
| 123888 | October 30 | Event | 1974 – The Rumble in the Jungle boxing match between Muhammad Ali and George Foreman takes place in Kinshasa, Zaire. Ali wins by KO in the eighth round, regaining the title of World Heavyweight Champion and causing Foreman´s first professional defeat. |
| 123889 | October 30 | Event | 1974 – As a member of the California Angels, Major League Baseball player Nolan Ryan throws the fastest recorded pitch, at 100.9 miles per hour (162.4 kilometers per hour). |
| 123890 | October 30 | Event | 1975 – Prince Juan Carlos becomes Spain's acting head of state, taking over for the country's ailing dictator, Gen. Francisco Franco. |
| 123891 | October 30 | Event | 1980 – El Salvador and Honduras sign a peace treaty to put the border dispute fought over in 1969's Football War before the International Court of Justice. |
| 123892 | October 30 | Event | 1983 – The first democratic elections in Argentina after seven years of military rule are held. |
| 123893 | October 30 | Event | 1985 – Space Shuttle Challenger lifts off for mission STS-61-A, its final successful mission. |
| 123894 | October 30 | Event | 1987 – In Japan, NEC releases the first 16-bit (fourth generation) video game console, the PC Engine, which is later sold in other markets under the name TurboGrafx-16. |
| 123895 | October 30 | Event | 1993 – The Troubles: The Ulster Defence Association, an Ulster loyalist paramilitary, carry out a mass shooting at a Halloween party in Greysteel, Northern Ireland. Eight civilians are murdered and thirteen wounded. |
| 123896 | October 30 | Event | 1995 – Quebec citizens narrowly vote (50.58% to 49.42%) in favour of remaining a province of Canada in their second referendum on national sovereignty. |
| 123897 | October 30 | Event | 2005 – The rebuilt Dresden Frauenkirche (destroyed in the firebombing of Dresden during World War II) is reconsecrated after a thirteen-year rebuilding project. |
| 123898 | October 30 | Event | 2013 – 45 people die after a bus fuel tank catches fire in the Indian city of Mahabubnagar. |
| 123899 | October 30 | Event | 2014 – Sweden is the first European Union member state to officially recognize the State of Palestine. |
| 123900 | October 30 | Birth | 39 BC – Julia the Elder, Roman daughter of Augustus (d. 14) |