The 20th century has told us many lessons. History does not repeat itself, but it appears that new variants of old themes keep coming back. Slowly passing the century like a movie in decades instead of episodes, we witness socio-emotional tides. The first decade, the 00s intensify the beginning of urban planning and social revolutions. The 10s show the arousal and subsequent extinction of masses of people in trenches. The 20s were described as the Carefree Twenties. In the 30s we observed the rising tides of fascist organisations followed shortly afterwards by the disastrous 40s. After the Shoah and the World War the 50s were fabulous viewed from the U.S. and Western Europe. The 60s propagated sex, drugs and rock n’ roll spreading across continents. The wild 70s became almost inescapable through the continued rise of mass media. The 80s were depicted as the colourful 80s as the 2 previous decades had set the scene for psychedelic colours. The 1990s have been coined as the gay 90s by some. Coming out as a gay person became easier and Western societies more sensitive and open to diversity. The back cover of the recent publication by Aurélien Bellanger “Le vingtième siècle” (The 20th century) speaks of the book as “roman polyphonique virtuose”. I look back on the 20th century as “polyphone” in many respects. It would be an illusion to believe we can only keep the nice sounding harmonies without the tensions or dissonances. 
40s
The years spanning from January 1940 to December 1949 are probably the worst to cramp into one decade. However, there are a few historians that use this approach to throw new light on a distant series of historical events in the 40s. The European perspective is dominated by war years and still has to deal with the unimaginable atrocities committed by Nazi-Germany until the end of the Second World War. From a more global historical perspective the war in the pacific also leaves lasting political changes, which are important to understand international politics and affairs of today. After a disastrous beginning with war for the USA for the decade, on the 10-12-1948 the United Nations (Charter Ratification 24-10-1945) General Assembly adopted the Universal Declaration of Human Rights. On the timeline at the end of the 40s we find the founding of NATO (4.4.1949) and (12-8-1949) the Geneva Convention which specifies internationally accepted laws of warfare. The beginning of the Cold War (Yalta and Potsdam Conferences in 1945) with strategies of containment and confrontation (Thomas Tandy Lewis, 2011 p.220), Berlin blockade determined a long-lasting concern for a balance of power across the world. The 40s were a market period of de-colonisation as well. The U.S. enabled struggles for independence to succeed with a sticks and carrots politics towards their wartime allies. The Marshall Plan for European Recovery is the most prominent example of this period. Ronald Goldberg (2012) includes a chapter on the home front in his summary of the forties in the U.S.A. After the 2nd World War all countries had to re-establish their societies and economies that had suffered due to lack of sometimes even caring for the most basic needs. Important lessons have to be learnt from the 1940s (Dave Renton, 2000 p.144) concerning how Fascists could rise and why, for example Britain, could resist the fascist movement. Anti-fascism in Britain during the 1940s and the importance to stop beginnings of an undemocratic political movement early and with the help of the police are 2 elements of the lessons learnt. Goldberg argues that it is less the Fascist ideology that conquered the minds of people, but the organisation as a political and para-military movement that is the more important threat to democracy. 
