Final answer:
The Soviet Union's collapse is unique because it happened mostly peacefully without widespread violence or external military intervention. It was a result of internal dynamics, mainly the reforms initiated by Mikhail Gorbachev.
Step-by-step explanation:
The collapse of the Soviet Union is considered a unique phenomenon due to several reasons. The main reason being that it was an event that occurred with minimal widespread violence or drastic territorial changes. Unlike many other historical power transitions or collapses of large empires, the Soviet Union dissolution was not a result of external military intervention.
Initiated by the reforms of Mikhail Gorbachev, the Soviet Union dissolution was more about the internal dynamics of the USSR than external pressures. These reforms, including political openness (Glasnost) and economic restructuring (Perestroika), were intended to modernize and save the Soviet Union, but ironically they facilitated its downfall.
By December 1991, the resistance to the central power culminated in a peaceful vote by the Soviet republics of Belarus, Ukraine, and Russia, represented by Boris Yeltsin, to dissolve the Soviet Union.
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