20thB-History

= **20th Century History** = Yifeng Tong

[[image:Presentation1.jpg width="337" height="258" align="left"]]Introduction
The twentieth century was defined by the dramatic reshaping of the world and the dynamic social changes that its people experienced. These changes were just as much the result of progress and change in all aspects of human civilization, as they were the result of the destructive forces of economic depression, world wars, and mass genocides. The century saw a drastic increase in world population: [|1.65 billion people in 1900 to 6.64 billion in 2000], but at the same time lost around 94 million people to two world wars and [|262 million people to actions by world governments]. At the beginning of the century, flight was the timeless dream that humankind had had for millennia. By the end of the twentieth century, humankind had landed on the moon and had sent missions to Mars. At the beginning of the century, only 14% of the world's population lived in urban areas, compared to the almost 50% that lived in urban areas at century's end. These statistics underscoring the vast changes the world experienced are limitless over 1900 to 2000.

Early 20th Century and World War I
At the beginning of the twentieth century, nationalism, the massive buildup of armed forces, and in Europe led to the first World War, which lasted from 1914 to 1918. The war involved most of the world's great powers at the time. Prior to the war, Great Britain, France and Russia committed to a military alliance. In 1882, Germany, Austria-Hungary and Italy signed a military alliance and the three powers became known as the [|Triple Alliance]. World War I threw the [|Triple Entente], which the United States later supports both militarily and economically, against the Central Powers, which included the Triple Alliance, the Ottoman Empire, and the Kingdom of Bulgaria. With more than 70 million military personnel involved, World War I is one of the largest wars in human history. Technological advances at the turn of the 20th century allowed the invention and mass production of [|new weapons], such as fighter airplanes, tanks, submarines, chemical weapons, and machine guns (see picture), all of which made World War I also one of the most deadliest wars in human history. Victory by the Triple Entente, after 15 million people killed by the end of the war, redefined borders and dissolved almost all the empires of the world that were created in the 17th to 19th centuries, including the Russian Empire, the German Empire, the Ottoman Empire, and the Austro-Hungarian Empire.



From Prosperity to Economic Depression
While the powers of Europe were wasting their landscapes and destroying their infrastructures in war, America, isolated from Europe with the moat of the Atlantic Ocean, remained untouched. American military involvement in the first World War was also minimal compared to the involvement of the more key nations. Therefore, the United States was given the opportunity in these four years to strengthen economically, with the help of industries contributing to the war effort, while Europe's progress was stunted by the war. The United States emerged from the turmoil of war an economic giant and a new world power, largely unscathed by World War I. Because of America's economic strength, during this time, the nations in Europe developed strong economic ties with America, which invested in the rebuilding of the war-torn continent. The 1920s was a dark decade of reconstruction in Europe, but in America, the decade became known as the [|"Roaring Twenties."] America experienced a period of social, artistic and cultural dynamism, resting on a solid economic foundation. During the 1920s, a wide array of consumer goods were introduced in America, such as personal automobiles and household appliances like washing machines and refrigerators. Much of these products were purchased by the rising American middle class on credit. The overuse of buying on credit, overwhelming agricultural surpluses, and instability of the nascent stock exchange eventually led to an economic downfall in America. The stock market crash came after a panic of selling on October 29, 1929, [|"Black Tuesday."] Just two months later, stockholders had lost $40 billion, more than the total cost of World War I to the United States (Kennedy, Cohen, and Bailey 768). The crash was only the beginning to a world-wide economic depression - America became very heavily involved economically with Europe, and once the American economy collapsed, European economies followed suit.

[[image:Bundesarchiv_Bild_183-S33882,_Adolf_Hitler_retouched.jpg width="159" height="243" align="left" caption="Adolf Hitler"]]World War II
World War II is arguably the highlight of the 20th century. Some scholars believe that all events in the 20th century have led up to the Second World War, and all events since have been a result of World War II. No scholars disagree, however, that World War II shaped the world like few other events in history ever have. 70 million people, mostly civilians, were killed during World War II, making it the deadliest conflict in history. After a crushing defeat in World War I, the terms of the [|Treaty of Versailles], the treaty that ended the first World War, upset the German people even further by forcing Germany to accept sole responsibility for causing the war and, under the the "War Guilt clauses", to disarm, make substantial territorial concessions and make reparations to certain countries that had been a part of the Entente. Already economically crippled from the war, and reparations totaling equivalent to $31.5 billion, the economic collapse of the United States heavily influenced the German post-war economy. In a time of intense poverty and national crisis, Austrian-born [|Adolf Hitler], a decorated veteran of World War I and leader of the National Socialist German Worker's Party (the [|Nazi]), essentially won the trust of the German people by charming oratory and attractive promises through propaganda. He was appointed Chancellor of Germany by President Paul Von Hindenburg, and from there established a totalitarian regime by quickly disposing of the president and subsequently taking power. He rapidly transformed the Weimar Republic to the Third Reich under a single-party dictatorship. Hitler desired to reassert Germany's power, influence and reputation in the world. In order establish his desired ultimate New Order of Nazi German hegemony in Europe, Hitler pursued a foreign policy that aggressively seized //Lebenstraum,// "living space" for his [|Aryan] people. Disregarding the terms of the Treaty of Versailles signed in 1919, Hitler rearmed Germany and invaded Poland. In response, Great Britain and France declared war on Germany, leading to another armed conflict involving multiple world powers, which became known as the Second World War. In September 1940, the Tripartite Pact was signed between Germany, Italy and Japan, forming the Axis Powers. Within three years, the Axis had occupied most of Europe, North Africa, East and Southeast Asia and the Pacific Ocean. 1942 brought the turning-point of the war, however, when the Soviet Union managed to hold off and push back the German advance. From 1942 on, the German army was sent on a retreat through Europe, back into the Fatherland. It was only at this time that the Allies managed to liberate the concentration and work camps at which Hitler's people performed horrible atrocities on and systematically murdered up to 17 million civilians, 6 million of which were Jews. In the Pacific theater, the Japanese navy invaded the American naval base at Pearl Harbor in December of 1941. Previously mostly militarily dormant, this attack put the United States into the war against the Axis Powers. The US joined sides with Britain and the Soviet Union (by this time France had already been conquered), and, unlike its small military role in World War I, contributed greatly to the victory in Europe. Germany surrendered in late April to early May of 1945. United States forces continued to push through the Pacific, 'island-hopping,' in a long and drawn-out process to reach the Japanese mainland. In an effort to save American military lives and to stop prolonging the conflict, President Truman authorized the dropping of two atomic bombs on Japanese cities - one dropped on Hiroshima on August 6 1945, killing directly approximately 80,000 people, and a second bomb dropped dropped on Nagasaki three days later, killing directly 40,000. The Japanese officially surrendered on September 2, ending World War II.

The United States and the Soviet Union
As wartime allies, the United States sought to get along with the Soviet Union to defeat a common enemy. Once the war was finished, however, the ideological differences between the United States and the Soviet Union were no longer ignored, and the United States dedicated itself to resistance against communism. Winston Churchill, in a speech delivered in March 1946, coined the term "Iron Curtain" to describe the schism through the European continent and the opposite ideologies followed by the two sides. The Berlin Wall, built to separate the occupational districts in the city after the German surrender, served as a tangible symbol of this "Iron Curtain." The Truman Doctrine was created in March of 1947 by President Harry S. Truman in a speech to Congress. He asserted that the United States was the "leader of the free world," and, as such, must support democracy worldwide and fight communism. The Truman Doctrine introduced the containment policy with regards to communism - that the United States would do its best to 'contain' communism to the Soviet Union. Later, the Marshall Plan, initiated in April 1948, was the primary plan of the United States to aid in the recovery of Europe after yet another World War. The program not only was meant to rebuild Europe, but also was intended to encourage resistance against communism. Over the next four decades, the United States and the Soviet Union were enemies in idealogy. An arms race and race to space ensued. The Soviet Union, over the years following the second World War, cut back on conventional military spending and invested in nuclear warheads capable of being launched, targeted at, and delivered to locations in the United States. As a result, in the United States, fear of the Soviet Union and communism was common, and at some points tension between the two nations arose to an extent that threatened nuclear war, which was discouraged with the doctrine of [|mutual assured destruction]. The race to space was another aspect of the American-Russian competition. In order to demonstrate technological supremacy and to research a method of delivery for nuclear weapons, the Soviet Union developed its space program following the second World War. When the Soviet Union launched Sputnik-1, the first man-made object in outer space, in October of 1957, it sent America in a temporary panic, and incited the establishment of the US space program. In April 1961, the Soviet Union once again pioneered a feat by sending Yuri Gagarin into outer space. Tension and close competition between the United States and the Soviet Union continued until 1991, when the Soviet Union collapsed.

The Korean and Vietnamese Conflicts
Also in an effort to contain communism, the United States became militarily involved in both Korea and Vietnam over the three decades following World War II. These dwarf in comparison against the international scale conflict that World War II was, but they demonstrate, on the surface, the commitment of the United States to containing communism, especially after China 'fell' to communism in the late 1950s, adding significantly to the already-substantial communist threat of the Soviet Union.

The Collapse of the Soviet Union
On November 9 1989, the Berlin Wall fell, symbolizing a major shift in the interaction between the East and the West.

[[image:content_berlin_wall.jpg width="184" height="142" align="right" caption="The Berlin Wall"]]
Coming into power in March of 1985, Mikhail Gorbachev, the leader of the Soviet Union, introduced a series of reforms that opened up the nation and loosened control, in addition to privatizing previously party-owned industries. When many former Soviet states pull away, Gorbachev, contrary to expectation, did not use force. Later, in a failed coup by a group led by the head of the KGB, Boris Yeltsin gained popularity by demanding and leading the people to demand an end to the coup. When Gorbachev was released from captivity by the KGB group, he faded away from importance in the government, and, on December 25th 1991, Gorbachev resigned the leadership of the Soviet Union. Within six days, the Soviet Union formally ceased to exist as its last leader with true communist ideals left office.

The Modern Era (The 1990s)
A combination of factors including the mass mobilization of capital markets through, the widespread proliferation of media such as the Internet, and the collapse of the Soviet Union led to a realignment and redistribution of economic and political power across the world, and within countries. Living standards and democratic governance generally improved in many areas of the world, notably East Asia, Eastern Europe, Latin America, and South Africa. However new ethnic conflicts emerged in Africa, the Caucusus and the Balkans, and conflicts in the Middle East remained strong.

[[image:hubble_earth_horz.jpg width="150" height="100" align="right" caption="The Hubble Telescope"]]
In scientific research, the period since the dissolution of the Soviet Union has been very fruitful - Dolly the sheep was cloned, stem cell research found its beginning, DNA technology matured to the extent that it would start to be used in this period in criminal law. Genetically engineered crops were beginning to be used commercially, and the [|Human Genome Project] began. The 1990s is associated also with unprecedented space exploration; with the launch of the [|Hubble Space Telescope] in 1990 and the first mission to Mars, mankind developed a greater understanding of the universe.