In the early 90s. XX century The Soviet multinational state, which lasted more than 70 years and, undoubtedly, had a huge impact on the course of world history, left the international political arena. As a result, a number of new states were formed that changed the geopolitical map of the world. One of the most important questions of modern history: why did the USSR collapse so unexpectedly? In order to reasonably answer this question, one should know not only the modern history of Russia, but also its past, and above all the history of the USSR.