1648 – University of Harderwijk Neth solemn opens
1940 – Italy annexes Albania
1955 – Polio vaccine tested by Dr Jonas Salk announced to be ‘safe and effective’
1964 – 28th US Masters Tournament, Augusta National GC: Arnold Palmer wins by 6 shots from Dave Marr and Jack Nicklaus to become the first 4-time winner of the Masters; his 7th and final major victory
1978 – Gyorgy Ligeti’s opera “Le Grand Macabre” premieres in Stockholm
1980 – Samuel Doe takes control of Liberia in a coup d’etat, ending over 130 years of national democratic presidential succession.
1985 – 16th Shuttle Mission (51D)-Discovery 4 launched-with Senator Jake Garn
1990 – H. J. Heinz, Chicken of the Sea and Bumble Bee Seafood say they wouldn’t buy tuna caught in nets that trap dolphins
1990 – 1st meeting of East German democratically elected parliament, acknowledges responsibility for the Holocaust and asks for forgiveness
1998 – An earthquake in Slovenia, measuring 5.6 on the Richter scale occurs near the town of Bovec.