On this day:
1582: Last day of the Julian Calendar in Catholic countries. The next day, the Gregorian calendar took effect in Italy, Poland, Portugal, and Spain by the order of Pope Gregory XIII.
1957: World’s first artificial satellite, Sputnik, launched
1966: Lesotho gained independence from British rule
Gone on this day:
1669: Rembrandt, Dutch painter
1951: Henrietta Lacks, American patient, HeLa cells derived from her cervical cancer