In what ways and why was 1979 such a watershed year?

In what ways and why was 1979 such awatershed year?  Or was it?  Explain.The answer should talk about global/world order, and making of 21st century.(ex: Iran, U.K. Afghanstan, Deng Xiaoping, etc.)This is an essay question, answer should be 350 words, and have clear points to support the idea.The work should be original and well-written.