1990: Batticaloa massacre: Massacre of 184 Tamil civilians by the Sri Lankan Army in Batticaloa District.
1972: In Kentucky's Mammoth Cave National Park, a Cave Research Foundation exploration and mapping team discovers a link between the Mammoth and Flint Ridge cave systems, making it the longest known cave passageway in the world.
1971: The four-day Attica Prison riot begins, eventually resulting in 39 dead, most killed by state troopers retaking the prison.
1965: Hurricane Betsy makes its second landfall near New Orleans, leaving 76 dead and $1.42 billion ($10-12 billion in 2005 dollars) in damages, becoming the first hurricane to cause over $1 billion in unadjusted damage.
1954: The 6.7 Mw Chlef earthquake shakes northern Algeria with a maximum Mercalli intensity of XI (Extreme). At least 1,243 people were killed and 5,000 were injured.
1948: Kim Il-sung declares the establishment of the Democratic People's Republic of Korea.
1944: World War II: The Fatherland Front takes power in Bulgaria through a military coup in the capital and armed rebellion in the country. A new pro-Soviet government is established.
1943: World War II: The Allies land at Salerno and Taranto, Italy.
1942: World War II: A Japanese floatplane drops incendiary bombs on Oregon.
1940: George Stibitz pioneers the first remote operation of a computer.
1939: Burmese national hero U Ottama dies in prison after a hunger strike to protest Britain's colonial government.
1939: World War II: The Battle of Hel begins, the longest-defended pocket of Polish Army resistance during the German invasion of Poland.
1936: The crews of Portuguese Navy frigate NRP Afonso de Albuquerque and destroyer Dão mutinied against the Salazar dictatorship's support of General Franco's coup and declared their solidarity with the Spanish Republic.
1855: Crimean War: The Siege of Sevastopol comes to an end when Russian forces abandon the city.
1850: The Compromise of 1850 transfers a third of Texas's claimed territory (now parts of Colorado, Kansas, New Mexico, Oklahoma, and Wyoming) to federal control in return for the U.S. federal government assuming $10 million of Texas's pre-annexation debt.
1850: California is admitted as the thirty-first U.S. state.
1839: John Herschel takes the first glass plate photograph.
1488: Anne becomes sovereign Duchess of Brittany, becoming a central figure in the struggle for influence that leads to the union of Brittany and France.
1379: Treaty of Neuberg, splitting the Austrian Habsburg lands between the Habsburg dukes Albert III and Leopold III.
1284: German warlord Trunda makes a campaign to Karelia to tax karelians but is defeated by Novgorod and the men from Staraya Ladoga.
337: Constantine II, Constantius II, and Constans succeed their father Constantine I as co-emperors. The Roman Empire is divided between the three Augusti.