Franklin D. Roosevelt is elected as President for the third time, central figure in world events during the mid-20th century, leading the USA during a time of worldwide economic depression and war. 75 years.
The Rhineland is remilitarized by the German Army: it was the first time since the end of WWI that German troops had been in this region, thus violating the terms of the Treaty of Versailles and the Locarno Treaties. 80 years.
Elizabeth Alexandra Mary, Her Majesty The Queen Elizabeth II was born and became Queen at the age of 25. She has reigned through more than five decades of enormous social change and development. 90 years.