5,963 articles
Oka Crisis
The Oka Crisis (Crise d'Oka), also the Kanehsatake Resistance, was a 78-day armed standoff, 11 July to 26 September 1990, between Mohawks of Kanehsatake and Kahnawake and Quebec police and the Canadian army over a golf course expansion on contested Mohawk land; SQ Cpl Marcel Lemay died on 11 July and the Royal Commission on Aboriginal Peoples followed.
Oklahoma City bombing
Oklahoma City bombing: April 19, 1995 truck bombing of the Alfred P. Murrah Federal Building by Timothy McVeigh and Terry Nichols; 168 killed, deadliest homegrown terrorist attack in U.S. history.
Old Location massacre
The Old Location massacre was the killing of unarmed protesters by police in Windhoek's Old Location, South West Africa, on 10 December 1959, during resistance to forced removal.
Oliver Otis Howard
Oliver Otis Howard (1830–1909), Union major general, first and only Freedmen's Bureau commissioner (1865–1872), founder and namesake of Howard University, later led the Nez Perce campaign and retired in 1894.
Omagh bombing
Omagh bombing: Real IRA car bomb in Omagh, County Tyrone, on 15 August 1998, four months after the Good Friday Agreement. Killed 29 plus two unborn children, injured about 300; no convictions, 2009 civil liability ruling, statutory inquiry since 2024.
Omaha Beach
Omaha Beach: American D-Day landing beach in Normandy, 6 June 1944, assaulted by the 1st and 29th Infantry Divisions; the most heavily defended and bloodiest of the five beaches, with about 2,400 casualties and the nickname Bloody Omaha.
Omaha race riot of 1919
Omaha race riot of 1919: a white mob stormed Omaha's Douglas County Courthouse on September 28, 1919, lynched Will Brown, nearly killed Mayor Edward P. Smith, and was linked by historians to Tom Dennison's political machine.
Omar bin Laden (عمر بن لادن)
Omar bin Laden (عمر بن لادن), fourth eldest son of Osama bin Laden and Najwa Ghanem, trained in his father's camps from 14, left at 18, co-authored Growing Up bin Laden, and became a peace advocate and painter.
Omar Mateen
Omar Mir Seddique Mateen, American-born security guard of Afghan descent, killed 49 people at Pulse gay nightclub, Orlando, June 12, 2016, pledging allegiance to ISIS before police killed him.
Omer Shem Tov (עומר שם טוב)
Omer Shem Tov (עומר שם טוב), an Israeli from Herzliya, was taken hostage by Hamas at the Nova music festival on October 7, 2023, held alone underground in Gaza tunnels for 505 days, and released on February 22, 2025; he now campaigns for remaining hostages.
On conducting a special military operation
On conducting a special military operation: Putin's 24 February 2022 televised address announcing the invasion of Ukraine (специальная военная операция, СВО), its stated goals of demilitarization and denazification, its legal framing, and its aftermath.
Ong Keo revolt
The Ong Keo revolt, or Holy Man's Uprising, was an armed uprising by highland groups against French rule on the Bolovens Plateau in southern Laos from 1901.
Ōnin War (応仁の乱)
Ōnin War (応仁の乱, Ōnin no Ran), 1467–1477 Japanese civil war in Kyoto between Hosokawa Katsumoto and Yamana Sōzen over Ashikaga shogunal succession; destroyed Kyoto, broke shugo power, and began the Sengoku Warring States period.
Operation 1027
Operation 1027, launched 27 October 2023 by Myanmar's Three Brotherhood Alliance (MNDAA, TNLA, Arakan Army) in northern Shan State, was the anti-junta offensive that inflicted the Tatmadaw's worst defeats in decades, capturing Laukkaing and inspiring nationwide resistance offensives.
Operation 1111
Operation 1111 was a coordinated offensive launched on 11 November 2023 by Karenni resistance forces against Myanmar's military regime, taking seven towns though never capturing the capital Loikaw.
Operation Agreement
Operation Agreement was a failed British-led amphibious and commando raid on the Axis-held port of Tobruk, Libya, on 13 September 1942, costing several hundred men killed or captured and three warships.
Operation Anaconda
Operation Anaconda, 2-16 March 2002, Shah-i-Kot Valley, Afghanistan: largest U.S. ground battle of the early Afghan War, led by Maj. Gen. Hagenbeck against al-Qaeda; planned 72-hour encirclement became a two-week fight marked by air-ground coordination failures.
Operation Arctic Endurance
Operation Arctic Endurance was a Danish-led military exercise in Greenland in January 2026, run under Danish national command rather than NATO, with seven European countries contributing troops.
Operation Astute
Operation Astute was the Australian-led international military and police intervention in Timor-Leste launched in May 2006 to restore security after the country's violent political crisis.
Operation Azm-e-Istehkam
Operation Azm-e-Istehkam is a 2024 Pakistani counter-terrorism campaign authorized by Prime Minister Shehbaz Sharif. It is a multi-domain national vision addressing security threats through political, socioeconomic, and kinetic measures.
Operation Babylift
Operation Babylift: 1975 US airlift authorized by President Ford on April 3 evacuating South Vietnamese orphans for intercountry adoption; 2,547 children processed, marred by the C-5A crash of April 4 that killed 138 including 78 children.
Operation Badr (عملية بدر) (1973)
Operation Badr (عملية بدر), Egypt's 6 October 1973 Suez Canal crossing opening the Yom Kippur/October War: five divisions, 4,000 first-wave troops, Bar Lev Line overrun, five bridgeheads, leading to the 24 October ceasefire and Camp David.
Operation Bagration (Операция «Багратион»)
Operation Bagration (Операция «Багратион»), the Belorussian Strategic Offensive Operation of 23 June to 29 August 1944, was the Red Army offensive that destroyed German Army Group Centre in Belarus, advanced up to 600 km, and is regarded in German historiography as Germany's largest military defeat.
Operation Baikal-79 (Операция «Байкал-79»)
Operation Baikal-79 (Операция «Байкал-79») was a Soviet operation by the 40th Army and KGB and GRU special forces that invaded Afghanistan on 25 December 1979, installing Babrak Karmal.
Operation Banner
Operation Banner: British Armed Forces operation in Northern Ireland, 14 August 1969 to 31 July 2007, supporting the RUC and PSNI during the Troubles; longest continuous UK deployment, over 300,000 personnel, 1,441 deaths, succeeded by Operation Helvetic.
Operation Barbarossa
Operation Barbarossa (Unternehmen Barbarossa) was Nazi Germany's June 22, 1941 invasion of the Soviet Union with over three million troops; the largest military operation in history, it failed at Moscow in December 1941 and opened the systematic mass murder of Soviet Jewry.
Operation Barkhane
Operation Barkhane was France's Sahel counterterrorism operation (1 August 2014 to 9 November 2022), successor to Serval, operating in Mauritania, Mali, Burkina Faso, Niger, and Chad with up to 5,100 troops before its Mali withdrawal and dissolution.
Operation Barras
Operation Barras, also called Operation Certain Death, was the 10 September 2000 British SAS, SBS, and Parachute Regiment hostage rescue at Gberi Bana and Magbeni, Sierra Leone, freeing six Royal Irish soldiers and a Sierra Leonean officer held by the West Side Boys.
Operation Barrel Roll
Operation Barrel Roll was a covert US air campaign over northern Laos from 1964 to 1973, supporting the Royal Lao Government and CIA-backed Hmong forces of General Vang Pao.
Operation Battleaxe
Operation Battleaxe was a failed British offensive in North Africa from 15 to 17 June 1941, launched to raise the siege of Tobruk during the Second World War.