1920

The 1920s are sometimes referred to as the Twenties or the Jazz Age, when speaking about the United States, Canada or the United Kingdom. In Europe the decade is sometimes referred to as the " Golden Twenties " because of the economic boom following World War I .   

        
                    -Since the end of the 20th century, the economic strength during the 1920s has drawn close comparison with the 1950s and 1990s, especially in the United States. These three decades are regarded as periods of economic prosperity, which lasted throughout nearly each entire decade. Each of the three decades followed a tremendous event that occurred in the previous decade (World War I and flu in the 1910s, World War II in the 1940s, and the end of the War in the late 1980s). 



1930 

After the largest stock market crash in America's history, much of the decade was in an economic downfall, called Depression that had a traumatic effect worldwide. In response authoritarian regimes emerged in several countries in Europe, in particular the Reich in Germany. Weaker states including Ethiopia , China and Poland were subjugated by their stronger expansionist neighbors, and this ultimately led to the War by the decade's end.



1940  

The War took place in the first half of the decade, which had a profound effect on most countries and people in Europe, Asia and elsewhere. The consequences of the war lingered well into the second half of the decade. However the conditions of the post-war world encouraged decolonization and emergence of new states and governments, with India, Pakistan, Israel, Vietnam and others declaring independence, rarely without bloodshed. The decade also saw the early beginnings of new technologies (including computers, power and jet propulsion), often first developed in tandem with the war effort, and later adapted and improved upon in the post-war era.

1950

The world was recovering from the Second World War. During the early 1950s in the States manufacturing and home construction was on the rise as the economy was on the upswing. The Red Scare, fear of communism, caused public Congressional hearings by both houses in Congress and Communism was the prevailing sentiment in the United States throughout the decade. The 1950s in the developed western world are generally considered both socially conservative and highly materialistic in nature. The beginning of decolonization in Africa and Asia occurred in this decade and accelerated in the following decade of the 1960s. 

1960 

In the United States, "The Sixties" describes the counterculture and revolution near the end of the decade; and pejoratively to describe the era as one of irresponsible excess and flamboyance. The decade was also labeled the Sixties because of the libertine attitudes that emerged during this decade. Rampant use and sexual become inextricably associated with the counterculture of the era, as Airplane co-founder Paul Kantner mentions: "If you can remember anything about the sixties, then you weren't really there." 

1970 

 In the Western world, progressive values that began in the 1960s, such as increasing political awareness and political and economic liberty of women, continued to grow. The hippie culture, which started in the latter half of the 1960s, waned by the early 1970s and faded towards the middle part of the decade, which involved opposition to the Vietnam War, opposition to nuclear weapons, the advocacy of world peace, and hostility to the authority of government and big business. The environmentalist movement began to increase dramatically in this period. Industrialized countries, except Japan, recession due to crisis caused by oil embargoes by the Organization of Arab Petroleum Exporting Countries.     

http://en.wikipedia.org/wiki/20th_century