The collapse of the Soviet Union occurred in 1991. This event marked the end of the Cold War and the beginning of a new era in world politics. The collapse of the Soviet Union had far-reaching consequences for the world, including the end of the bipolar world order, the rise of the United States as the dominant superpower, and the emergence of new states in Eastern Europe and Central Asia.

Factors leading to the collapse of the Soviet Union:

1. Economic troubles: The Soviet economy was struggling, with declining productivity, widespread corruption, and a shortage of basic goods.

2. Political instability: The Soviet political system was characterized by corruption, nepotism, and a lack of transparency, which eroded public trust in the government.

3. Nationalism: The Soviet Union was a multi-ethnic state, with many different nationalities and languages. As the Soviet system began to crumble, nationalist movements emerged in many of the republics, demanding greater autonomy or even independence.

4. Perestroika and glasnost: The policies of perestroika (restructuring) and glasnost (openness) implemented by Soviet leader Mikhail Gorbachev in the 1980s had unintended consequences, including the erosion of central control over the Soviet economy and society.

5. Arms race: The Soviet Union was engaged in an arms race with the United States, which placed a heavy burden on the Soviet economy and contributed to the country's economic troubles.

Events leading to the collapse of the Soviet Union:

1. The Baltic republics: In 1990, the Baltic republics (Estonia, Latvia, and Lithuania) declared independence from the Soviet Union, sparking a wave of nationalism throughout the country.

2. The August Coup: In August 1991, a group of hardline Communist officials attempted to oust Gorbachev and seize power. The coup failed, but it weakened Gorbachev's position and paved the way for the collapse of the Soviet Union.

3. The Belavezha Accords: In December 1991, the leaders of Russia, Belarus, and Ukraine signed the Belavezha Accords, which dissolved the Soviet Union and created the Commonwealth of Independent States (CIS).

The collapse of the Soviet Union had far-reaching consequences, including the emergence of new states in Eastern Europe and Central Asia, the end of the bipolar world order, and the rise of the United States as the dominant superpower.