Brunei: Royal Brunei Armed Forces Day
1223 - Mongol invasion of the Cumans: Battle of the Kalka River – Mongol armies of Genghis Khan led by Subutai defeat Kievan Rus and Cumans.
1279 BC - Rameses II (The Great) (19th dynasty) becomes pharaoh of Ancient Egypt.
1578 - Martin Frobisher sails from Harwich, England to Frobisher Bay, Canada, eventually to mine fool's gold, used to pave streets in London.
1669 - Citing poor eyesight, Samuel Pepys records the last event in his diary.
1678 - The Godiva procession through Coventry begins.
1759 - The Province of Pennsylvania bans all theater productions.
1775 - American Revolution: The Mecklenburg Resolutions adopted in the Province of North Carolina
1790 - Alferez Manuel Quimper explores the Strait of Juan de Fuca.
1790 - The United States enacts its first copyright statute, the Copyright Act of 1790.
1813 - In Australia, Lawson, Blaxland and Wentworth, reached Mount Blaxland, effectively marking the end of a route across the Blue Mountains.
1859 - The clock tower at the Houses of Parliament, which houses Big Ben, starts keeping time.
1862 - American Civil War Peninsula Campaign: Battle of Seven Pines or (Battle of Fair Oaks) – Confederate forces under Joseph E. Johnston & G. W. Smith engage Union forces under George B. McClellan outside Richmond, Virginia.
1864 - American Civil War Overland Campaign: Battle of Cold Harbor – The Army of Northern Virginia under Robert E. Lee engages the Army of the Potomac under Ulysses S. Grant & George G. Meade.
1866 - In the Fenian Invasion of Canada, John O'Neill leads 850 Fenian raiders across the Niagara River at Buffalo, New York/Fort Erie, Ontario, as part of an effort to free Ireland from the English. Canadian militia and British regulars repulse the invaders in over the next three days, at a cost of 9 dead and 38 wounded to the Fenian's 19 dead and about 17 wounded.
1889 - Johnstown Flood: Over 2,200 people die after a dam break sends a 60-foot (18-meter) wall of water over the town of Johnstown, Pennsylvania.
1902 - Second Boer War: The Treaty of Vereeniging ends the war and ensures British control of South Africa.
1910 - Creation of the Union of South Africa.
1911 - R.M.S. Titanic launched.
1916 - World War I: Battle of Jutland – The British Grand Fleet under the command of Sir John Jellicoe & Sir David Beatty engage the Kaiserliche Marine under the command of Reinhard Scheer & Franz von Hipper in the largest naval battle of the war, which proves indecisive.
1921 - Tulsa Race Riot: A civil unrest in Tulsa, Oklahoma, United States, the official death toll is 39, but recent investigations suggest the actual toll may be much higher.
1924 - The Soviet Union signs an agreement with the Peking government, referring to Outer Mongolia as an "integral part of the Republic of China", whose "sovereignty" therein the Soviet Union promises to respect.
1927 - The last Ford Model T rolls off the assembly line after a production run of 15,007,003 vehicles.
1931 - 7.1 magnitude Earthquake destroys Quetta in modern-day Pakistan: 40,000 dead.
1941 - A Luftwaffe air raid in Dublin, Ireland claims 38 lives.
1942 - World War II: Imperial Japanese Navy midget submarines begin a series of attacks on Sydney, Australia.
1943 - Zoot Suit Riots begin
1961 - Republic of South Africa created.
1962 - The West Indies Federation dissolves.
1962 - Adolf Eichmann is hanged in Israel.
1970 - The Ancash earthquake causes a landslide that buries the town of Yungay, Peru; more than 47,000 people are killed.
1971 - In accordance with the Uniform Monday Holiday Act passed by the U.S. Congress in 1968, observation of Memorial Day occurs on the last Monday in May for the first time, rather than on the traditional Memorial Day of May 30.
1973 - The United States Senate votes to cut off funding for the bombing of Khmer Rouge targets within Cambodia, hastening the end of the Cambodian Civil War.
1977 - The Trans-Alaska Pipeline System completed.
1981 - Burning of Jaffna library, Sri Lanka, It is one of the violent examples of ethnic biblioclasm of the twentieth century.
1985 - 1985 United States-Canadian tornado outbreak: Forty-one tornadoes hit Ohio, Pennsylvania, New York, and Ontario, leaving 76 dead.
1985 - Methylenedioxymethamphetamine (MDMA) became a Schedule I drug in the United States.
1987 - Athena 98.4 FM, the first legal private radio station starts broadcasting in Greece.