1955
Events
January
- January 3 – José Ramón Guizado becomes president of Panama.
- January 17 –, the first nuclear-powered submarine, puts to sea for the first time, from Groton, Connecticut.
- January 18–20 – Battle of Yijiangshan Islands: The Chinese Communist People's Liberation Army seizes the islands from the Republic of China.
- January 22 – In the United States, The Pentagon announces a plan to develop intercontinental ballistic missiles, armed with nuclear weapons.
- January 23 – The Sutton Coldfield rail crash kills 17, near Birmingham, England.
- January 25 – The Presidium of the Supreme Soviet of the Soviet Union announces the end of the war between the USSR and Germany, which began during World War II in 1941.
- January 28 – The United States Congress authorizes President Dwight D. Eisenhower to use force to protect Taiwan from the People's Republic of China.
February
- February 10 – The United States Seventh Fleet helps the Republic of China evacuate the Chinese Nationalist army and residents from the Tachen Islands to Taiwan.
- February 16 – Nearly 100 die in a fire at a home for the elderly in Yokohama, Japan.
- February 19 – The Southeast Asia Treaty Organization is established, at a meeting in Bangkok.
- February 22 – In Chicago's Democratic primary, Mayor Martin H. Kennelly loses to the head of the Cook County Democratic Party, Richard J. Daley, 364,839 to 264,077.
- February 24 – The Baghdad Pact, originally known as Middle East Treaty Organization, is signed between Iraq and Turkey.
March
- March 2 – Claudette Colvin, a 15-year-old African-American girl, refuses to give up her seat on a bus in Montgomery, Alabama, to a white woman after the driver demands it. She is carried off the bus backwards, while being kicked, handcuffed and harassed on the way to the police station. She becomes a plaintiff in Browder v. Gayle, which rules bus segregation to be unconstitutional.
- March 20 – The movie adaptation of Evan Hunter's novel Blackboard Jungle premieres in the United States, featuring the famous single "Rock Around the Clock" by Bill Haley & His Comets. Teenagers jump from their seats to dance to the song.
April
- April 1 – EOKA starts a resistance campaign against British rule in the Crown colony of Cyprus.
- April 5
- * Winston Churchill resigns as Prime Minister of the United Kingdom, due to ill-health, at the age of 80.
- * Richard J. Daley defeats Robert Merrian to become Mayor of Chicago, by a vote of 708,222 to 581,555.
- April 6 – Anthony Eden becomes Prime Minister of the United Kingdom.
- April 11
- * The Taiwanese Kuomintang put a bomb on the airplane Kashmir Princess, killing 16 but failing to assassinate the People's Republic of China leader, Zhou Enlai.
- * Taekwondo, a form of Korean martial arts, is officially recognized in South Korea. A board convened by General Choi Hong Hi, including master instructors, historians and societal leaders, officially adopts the name Taekwon-Do for the unified Korean martial art.
- April 12 – The Salk polio vaccine, having passed large-scale trials earlier in the United States, receives full approval by the Food and Drug Administration.
- April 15 – The first franchised McDonald's restaurant is opened by Ray Kroc, in Des Plaines, Illinois.
- April 16 – The Burma–Japan Peace Treaty, signed in Rangoon on November 5, 1954, comes into effect, formally ending a state of war between the two countries.
- April 17 – Imre Nagy, the communist Premier of Hungary, is ousted for being too moderate.
- April 18–24 – The Asian-African Conference is held in Bandung, Indonesia.
May
- May 5 – West Germany becomes a sovereign country, recognized by Western countries such as France, the United Kingdom, Canada and the United States.
- May 6 – The Western European Union Charter becomes effective.
- May 7 – Newcastle United F.C. beat Manchester City F.C. 3–1 to win the 1955 FA Cup final in English Association football.
- May 9 – West Germany joins the North Atlantic Treaty Organization.
- May 11 – Japanese National Railways' ferry Shiun Maru sinks after a collision with sister ship Uko Maru, in thick fog off Takamatsu, Shikoku, in the Seto Inland Sea of Japan; 166 passengers and 2 crew members are killed. This event is influential in plans to construct the Akashi Kaikyō Bridge.
- May 14 – Eight Communist Bloc countries, including the Soviet Union, sign a mutual defence treaty in Warsaw, Poland, that is called the Warsaw Pact.
- May 15
- * The Austrian State Treaty, which restores Austria's national sovereignty, is concluded between the 4 occupying powers following World War II and Austria, setting it up as a neutral country.
- * Lionel Terray and Jean Couzy become the first people to reach the summit of Makalu, the fifth-highest mountain in the world, on the 1955 French Makalu expedition. The entire team of climbers reaches the summit over the next two days.
- May 18 – Free movement of residents between North and South Vietnam ends.
- May 25 – Joe Brown and George Band are the first to climb Kangchenjunga in the Himalayas, as part of the British Kangchenjunga expedition led by Charles Evans.
June
- June 7 – The television quiz program The $64,000 Question premieres on CBS-TV in the United States, with Hal March as the host.
- June 11 – Le Mans disaster: Eighty-three people are killed and at least 100 are injured after two race cars collide in the 1955 24 Hours of Le Mans.
- June 13 – Mir mine, the first diamond mine in the Soviet Union, is discovered.
- June 26 – The Freedom Charter of the anti-apartheid South African Congress Alliance is adopted, at a Congress of the People in Kliptown.
- June 30 – The Simonstown Agreement provides for control of the naval base at Simon's Town in the Union of South Africa to transfer from the British Royal Navy to the South African Navy.
July
- July 7 – The New Zealand Special Air Service is formed.
- July 13 – Ruth Ellis is hanged for murder in London, becoming the last woman ever to be executed in the United Kingdom.
- July 17
- * The Disneyland theme park opens in Anaheim, California, an event broadcast on the American Broadcasting Company television network.
- * The first atomic-generated electrical power is sold commercially, partially powering Arco, Idaho, from the U.S. National Reactor Testing Station; on July 18, Schenectady, New York, receives power from a prototype nuclear submarine reactor at Knolls Atomic Power Laboratory.
- July 18 - Illinois Governor William Stratton signs the Loyalty Oath Act, that mandates all public employees take a loyalty oath to the State of Illinois and the United States or lose their jobs.
- July 18–23 – Geneva Summit between the United States, Soviet Union, United Kingdom and France.
- July 27 – El Al Flight 402 from Vienna to Tel Aviv, via Istanbul, is shot down over Bulgaria. All 58 passengers and crewmen aboard the Lockheed Constellation are killed.
- July 28 – The first Interlingua Congress is held in Tours, France, leading to the foundation of the Union Mundial pro Interlingua.
August
- August 1 – The prototype Lockheed U-2 reconnaissance aircraft first flies, in Nevada.
- August 18
- * The First Sudanese Civil War begins.
- * The first meeting of the Organization of Central American States is held, in Antigua Guatemala.
- August 19 – Hurricane Diane hits the northeastern United States, killing over 200 people and causing over $1 billion in damage.
- August 20 – Hundreds of people are killed in anti-French rioting in Morocco and Algeria.
- August 22 – Eleven schoolchildren are killed when their school bus is hit by a freight train in Spring City, Tennessee.
- August 25 – The last Soviet Army forces leave Austria.
- August 26 – Satyajit Ray's film Pather Panchali is released in India.
- August 27 – The first edition of the Guinness Book of Records is published, in London.
- August 28 – Black 14-year-old Emmett Till is lynched and shot in the head for allegedly whistling at a white woman in Money, Mississippi; his white murderers, Roy Bryant and J. W. Milam, are acquitted by an all-white jury.
September
- September 2 – Under the guidance of Dr. Humphry Osmond, Christopher Mayhew ingests 400 mg of mescaline hydrochloride and allows himself to be filmed as part of a Panorama special for BBC TV in the U.K. that is never broadcast.
- September 3 – Little Richard records "Tutti Frutti" in New Orleans; it is released in October.
- September 6 – Istanbul pogrom: Istanbul's Greek minority is the target of a government-sponsored pogrom.
- September 10 – The long-running Western television series Gunsmoke debuts, on the CBS network in the United States.
- September 14 – Pope Pius XII elevates many of the apostolic vicariates in Africa to Metropolitan Archdioceses.
- September 15 – Vladimir Nabokov's controversial novel Lolita is published in Paris, by Olympia Press.
- September 16
- * The military coup to unseat President Juan Perón of Argentina is launched at midnight.
- * A Soviet Navy Zulu-class submarine becomes the first to launch a ballistic missile.
- September 18 – The United Kingdom formally annexes the uninhabited Atlantic island of Rockall.
- September 19–21 – President of Argentina Juan Perón is ousted in a military coup.
- September 19 – Hurricane Hilda kills about 200 people in Mexico.
- September 21–30 – Hurricane Janet, one of the strongest North Atlantic tropical cyclones on record, sweeps the Lesser Antilles and Mexico, causing more than 1,020 deaths.
- September 22 – Commercial television starts in the United Kingdom with the Independent Television Authority's first ITV franchises beginning broadcasting in London, ending the BBC monopoly.
- September 24
- * Dwight D. Eisenhower, president of the United States, suffers a coronary thrombosis while on vacation in Denver, Colorado. Vice President Nixon assumed administrative duties and presided over Cabinet and National Security Council meetings while Eisenhower recovers.
- * Founder of Swiss watchmaker Glycine Watch SA, Eugène Meylan, age 64, is murdered.
- September 30 – Actor James Dean is killed when his automobile collides with another car at a highway junction, near Cholame, California.