On January 10, 1946 the first meeting of the General Assembly of the United Nations took place in London, with 51 members. The Norwegian Foreign Minister Trygve Lie, was elected as the first UN Secretary-General.
The United Nations has six principle organs, with the following functions
The General Assembly (deliberation)
The Security Council (resolutions for peace and security)
The Economic and Social Council (promoting international economic and social cooperation )
Secretariat (providing studies and information)
The International Court of Justice
The UN Trusteeship Council (inactive since 1994)
UN System agencies include The World Bank Group, The World Health Organization, The World Food Programme, UNESCO (United Nations Educational, Science, and Cultural Organization) and UNICEF (United Nations Children’s Fund)
The current Secretary-General of the UN is António Guterres of Portugal.
These posts are true to the best of my knowledge at the time of writing. I make no claims to their accuracy. The purpose is to inform, educate, amuse, and make people aware of causes and opportunities around the world. I also encourage civil debate in the comment section.