When was the United Nations established?

The United Nations was established in 1945 in the aftermath of World War II, with the objective of promoting international cooperation and preventing future conflicts. The founding conference took place in San Francisco, where representatives from 50 countries gathered to draft the UN Charter. This significant moment in history reflected a collective desire to foster peace, security, and development on a global scale following the devastating consequences of the war.

The other years presented in the options do not align with the founding of the United Nations. For example, 1948 is notable for the adoption of the Universal Declaration of Human Rights, but the UN itself was already operational by that time. The year 1950 does not hold significance for the UN's establishment, and 1939, which marks the beginning of World War II, is prior to the formation of the UN. Thus, 1945 is the key year that marks the establishment of this pivotal organization.