Explain the purpose, principles and membership of the United Nations.

The Charter's road: the League's failures and the Second World War's shock → the Atlantic Charter (1941) and the Declaration by United Nations (1942) → the Moscow (1943) and Dumbarton Oaks (1944) conversations → Yalta's settlement of the voting question → the San Francisco Conference (April-June 1945): fifty states drafting and signing the Charter (26 June 1945); entry into force 24 October 1945 (UN Day). The design's novelties against the League: the Security Council's primary responsibility with the P5's special role; the specialized- agency family (Articles 57-63); the weighted voting of the councils; the self-determination and human-rights clauses; the trusteeship succession. Membership's growth: 51 founders → 193 members (the last admission: South Sudan, 2011) — the decolonization wave's monument.