On this day...
- 1811 – Peninsular War: An allied force of British, Spanish, and Portuguese troops clashed with the French at the Battle of Albuera south of Badajoz, Spain.
- 1843 – The first major wagon train heading for the Pacific Northwest set out on the Oregon Trail (reenactment pictured) with a thousand pioneers from Elm Grove, Missouri.
- 1918 – The Sedition Act was passed in the United States, forbidding Americans from using "disloyal, profane, scurrilous, or abusive language" about the United States government, flag, or armed forces during the ongoing World War I.
- 1943 – Royal Air Force Dambusters embarked on a raid to deploy bouncing bombs on German dams in Operation Chastise during the Second World War.
- 1961 – The Military Revolution Committee, led by Park Chung-hee, carried out a bloodless coup against the government of Yun Bo-seon, ending the Second Republic of South Korea.