May 27
• 1905 – Russo-Japanese War: The Battle of Tsushima begins.
• 1907 – Bubonic plague breaks out in San Francisco.
• 1908 – Khilafat Day – the day of establishment of Khilafat in Islam Ahmadiyya.
• 1917 – Pope Benedict XV promulgates the 1917 Code of Canon Law, the first comprehensive codification of Catholic canon law in the legal history of the Catholic Church.
• 1919 – The NC-4 aircraft arrives in Lisbon after completing the first transatlantic flight.
• 1927 – The Ford Motor Company ceases manufacture of the Ford Model T and begins to retool plants to make the Ford Model A.
• 1930 – The 1,046 feet (319 m) Chrysler Building in New York City, the tallest man-made structure at the time, opens to the public.
• 1933 – New Deal: The U.S. Federal Securities Act is signed into law requiring the registration of securities with the Federal Trade Commission.
• 1933 – The Walt Disney Company releases the cartoon Three Little Pigs, with its hit song "Who's Afraid of the Big Bad Wolf?"
• 1933 – The Century of Progress World's Fair opens in Chicago.
• 1935 – New Deal: The Supreme Court of the United States declares the National Industrial Recovery Act to be unconstitutional in A.L.A. Schechter Poultry Corp. v. United States, (295 U.S. 495).
• 1937 – In California, the Golden Gate Bridge opens to pedestrian traffic, creating a vital link between San Francisco and Marin County, California.
• 1940 – World War II: In the Le Paradis massacre, 99 soldiers from a Royal Norfolk Regiment unit are shot after surrendering to German troops; two survive.
• 1941 – World War II: U.S. President Franklin D. Roosevelt proclaims an "unlimited national emergency".
• 1941 – World War II: The German battleship Bismarck is sunk in the North Atlantic killing almost 2,100 men.
• 1942 – World War II: In Operation Anthropoid, Reinhard Heydrich is fatally wounded in Prague; he dies of his injuries eight days later.
• 1958 – The F-4 Phantom II makes its first flight.
• 1960 – In Turkey, a military coup removes President Celâl Bayar and the rest of the democratic government from office.
• 1962 – The Centralia mine fire is ignited in the town's landfill above a coal mine.
• 1965 – Vietnam War: American warships begin the first bombardment of National Liberation Front targets within South Vietnam.
• 1967 – Australians vote in favor of a constitutional referendum granting the Australian government the power to make laws to benefit Indigenous Australians and to count them in the national census.
• 1967 – The U.S. Navy aircraft carrier USS John F. Kennedy is launched by Jacqueline Kennedy and her daughter Caroline.
• 1968 – The meeting of the Union Nationale des Étudiants de France (National Union of the Students of France) takes place. 30,000 to 50,000 people gather in the Stade Sébastien Charléty.
• 1968 – Major League Baseball's National League awards Montreal the first franchise in Canada and the first franchise outside the United States. (the Montreal Expos)
• 1971 – The Dahlerau train disaster, the worst railway accident in West Germany, kills 46 people and injures 25 near Wuppertal.
• 1975 – Dibbles Bridge coach crash near Grassington, in North Yorkshire, England, kills 33 – the highest ever death toll in a road accident in the United Kingdom.
• 1980 – The Gwangju Massacre: Airborne and army troops of South Korea retake the city of Gwangju from civil militias, killing at least 207 and possibly many more.
• 1986 – Dragon Quest, the game credited as setting the template for role-playing video games, is released in Japan.
• 1995 – In Culpeper, Virginia, the actor Christopher Reeve is paralyzed from the neck down after falling from his horse in a riding competition.
• 1995 – The 7.0 Mw Neftegorsk earthquake shakes northern Sakhalin Island in Russia with a maximum Mercalli intensity of IX (Violent), leaving 1,989 people dead and 750 injured.
• 1996 – First Chechen War: the Russian President Boris Yeltsin meets with Chechnyan rebels for the first time and negotiates a cease-fire.
• 1997 – The unusual tornado outbreak in Jarrell, Texas.
• 1997 – The U.S. Supreme Court rules that Paula Jones can pursue her sexual harassment lawsuit against President Bill Clinton while he is in office.
• 1998 – Oklahoma City bombing: Michael Fortier is sentenced to 12 years in prison and fined $200,000 for failing to warn authorities about the terrorist plot.
• 2001 – Members of the Islamist separatist group Abu Sayyaf seize twenty hostages from an affluent island resort on Palawan in the Philippines; the hostage crisis would not be resolved until June 2002.
• 2006 – The 6.4 Mw Yogyakarta earthquake shakes central Java with an MSK intensity of IX (Destructive), leaving more than 5,700 dead and 37,000 injured.
• 2016 – Barack Obama is the first president of United States to visit Hiroshima Peace Memorial Park and meet Hibakusha.