The 20th century was dominated by global conflicts, rapid technological innovation, the bipolar struggle of the Cold War, and the decolonization movement that fundamentally changed the political map.

• Major Events
  1. World War I (1914–1918 CE) and World War II (1939–1945 CE) devastate global populations.
  2. The Cold War between the United States and the Soviet Union dominates geopolitics (post-1945).
  3. The Space Race leads to the moon landing (1969 CE).
  4. The collapse of the Soviet Union (1991 CE), ending the Cold War.
• Major Powers
  1. United States (Becomes the sole global superpower after 1991)
  2. Soviet Union (Major superpower until 1991)
  3. United Nations (Established 1945 CE)
  4. China (Emerges as a major economic power late century)
• Major Conflicts
  1. World War I (1914–1918 CE)
  2. World War II (1939–1945 CE)
  3. Vietnam War, Korean War, proxy wars of the Cold War.
• Population Trends
  1. Explosive global population growth (quadrupling by the end of the century).
  2. Massive civilian casualties in wars, genocides, and man-made famines.
• Key Leaders
  1. Franklin D. Roosevelt / Winston Churchill / Joseph Stalin (WWII era)
  2. Mahatma Gandhi (Leader of Indian independence movement)
  3. Nelson Mandela (Anti-apartheid revolutionary, later President of South Africa)
• Key Intellectuals
  1. Albert Einstein (Physicist, developed the theory of relativity) [Image of Albert Einstein]
  2. John Maynard Keynes (Economist, revolutionized macroeconomic thought)
  3. Martin Luther King Jr. (Civil rights activist)
• Major Religions
  1. Christianity (Continues global growth, shifting centers of gravity to the Global South).
  2. Islam (Rise of Islamic revivalism and political Islam).
  3. Secularism and Atheism increase, particularly in developed nations.
• Key Developments
  1. Development of nuclear weapons and atomic energy.
  2. The invention of the transistor, microchip, and personal computer.
  3. Major medical advances: antibiotics, vaccines, and DNA structure discovery.