The main arena of conflict between the superpowers during the Cold War was Europe. This was due to a number of factors, including:

1. The division of Europe: After World War II, Europe was divided into Western Europe and Eastern Europe, with the Western countries aligned with the United States and the Eastern countries aligned with the Soviet Union. This division created a natural conflict between the two superpowers as they sought to expand their influence and gain control over the continent.

2. The arms race: Both the United States and the Soviet Union engaged in an arms race during the Cold War, with each side building up their military capabilities in an effort to gain an advantage over the other. This led to a buildup of military forces in Europe, which increased tensions and made the region a potential flashpoint for conflict.

3. The Berlin Wall: The construction of the Berlin Wall in 1961 symbolized the division of Europe and became a key symbol of the Cold War. The wall separated East and West Berlin and was a physical manifestation of the ideological divide between the United States and the Soviet Union.

4. Proxy wars: The United States and the Soviet Union fought a number of proxy wars in Europe during the Cold War, including the Korean War and the Vietnam War. These conflicts were fought indirectly through local allies and were often a means for the two superpowers to gain influence in the region.

In conclusion, the main arena of conflict between the superpowers during the Cold War was Europe. The division of Europe, the arms race, the Berlin Wall, and proxy wars were all factors that contributed to the tensions and conflicts in the region.