Why was the UN formed?

You must have heard of the UN or the United Nations, but do you know what it is, and why it was formed? The United Nations is an international or­ganisation of countries created to promote world peace and cooperation. The seeds of the United Nations were sown many years earlier in another organisation called the League of Nations. It was formed after World War I, to ensure that in future, nations would settle all disputes peacefully without going to war. The League of Nations failed in this objective, and the world had to suffer an­other World War in 1939. The reason for the League's failure was that many powerful states, including Russia and the USA, remained outside the League. The UN was founded after World War II ended in 1945. Its mission is to maintain world peace, develop good relations between countries, promote cooperation in solving the world's problems, and encourage respect for human rights.
The UN is an organisation of countries that agree to cooperate with one another. It brings together countries that are rich and poor, large and small, and have different social and political systems. Member nations pledge to settle their disputes peacefully, to refrain from using force or the threat of force against other countries, and to refuse help to any country that opposes UN actions.
UN membership is open to any country willing to further the UN mission and abide by its rules. Every member country is expected to pay dues to support the UN. As of 2007, the UN had 192 members, including nearly every country in the world.