Day of Declaration of Sovereignty in Estonia (1988)
1384 – Jadwiga (pictured) was officially crowned as "King of Poland" instead of "Queen" to reflect the fact that she was a sovereign in her own right and not merely a royal consort.
1491 – Several Jews and conversos were executed in Toledo, Spain, for the alleged ritual murder of an infant, who was later revered as the Holy Child of La Guardia.
1855 – Explorer David Livingstone became the first European to see Victoria Falls, one of the largest waterfalls in the world, on what is now the Zambia–Zimbabwe border.
1938 – Swiss chemist Albert Hofmann first synthesized the psychedelic drug LSD at the Sandoz Laboratories in Basel, Switzerland.
1992 – In Suffolk, England, an amateur metal detectorist found the largest hoard of Roman gold, silver and bronze coins from the late fourth and early fifth centuries ever discovered within the former Roman Empire.