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