The Cold War refers to a period of geopolitical tension and competition between the United States and its allies (primarily NATO) and the Soviet Union and its allies (primarily the Eastern Bloc) following World War II. The term "cold" signifies that while there was no direct military conflict between the two superpowers, there was intense ideological, political, economic, and military rivalry.

Key features of the Cold War included:

1. Ideological Conflict: The Cold War was characterized by ideological differences between the capitalist, democratic values of the West (led by the United States) and the communist ideology of the Soviet Union and its allies.

2. Arms Race: Both sides engaged in a massive buildup of nuclear weapons and other military technologies, leading to an arms race that heightened tensions and created the constant threat of mutual destruction.

3. Proxy Wars: While direct conflict between the US and USSR was avoided, both sides engaged in proxy wars in various regions around the world. These conflicts often involved supporting opposing factions or governments, leading to significant human and material costs.

4. Space Race: A competition for technological and ideological superiority played out in the realm of space exploration, with both the US and the USSR striving to achieve milestones such as putting the first satellite, animal, and human in space.

5. Espionage and Intelligence Operations: Both sides engaged in extensive espionage and intelligence operations to gather information, undermine each other's interests, and gain strategic advantages.

6. Economic Competition: The Cold War also saw economic competition between the capitalist system of the West and the centrally planned economy of the Soviet bloc. This competition extended to areas such as trade, development aid, and technological innovation.

The Cold War officially ended with the collapse of the Soviet Union in 1991, marking the victory of the United States and the West in the ideological and geopolitical struggle. However, its legacy continues to shape international relations, particularly in areas such as nuclear proliferation, regional conflicts, and great power rivalry.

India signed the Treaty of Peace, Friendship, and Cooperation with the Soviet Union on August 9, 1971. The treaty was signed during a period of heightened tension between India and Pakistan, leading up to the Bangladesh Liberation War. India sought support from the Soviet Union due to its longstanding relationship and strategic interests. The treaty was aimed at bolstering India's security and securing Soviet assistance in the event of conflict with Pakistan or China. Additionally, it served as a counterbalance to Pakistan's alliance with the United States.