1850: Robert McClure sights the fabled Northwest Passage for the first time, from Banks Island towards Melville Island

1861: The Pony Express (Missouri to California) ends after 19 months

1863: International conference begins in Geneva aimed at improving medical conditions on battlefields, leads to the formation of the Red Cross

1977: Last natural case of smallpox is discovered in Merca District, Somalia, and is considered the anniversary of the eradication of smallpox, the most spectacular success of vaccination

2019: Raid by US Special Forces kills ISIS founder and leader Abu Bakr al-Baghdadi in Syria

Source: Onthisday.com