The powerful UN Security Council in October agreed on a deal to eliminate Syria's chemical weapons stockpiles by mid-2014 after days of back-room negotiations.
The Organisation for Prohibition of Chemical Weapons - the body supervising the dismantling of the Syrian chemical weapons - won the 2013 Nobel Peace Prize for its achievement.
The deal consists of a short-term freeze of portions of nuclear programme in exchange for decreased economic sanctions on Iran, as the countries work towards a long-term agreement.
But all was not well for the UN in 2013, as the year also brought sad news for the world body and India, one of the major troops contributing countries to peacekeeping missions.
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The attack was the second in eight months in South Sudan, the newest country in the world, in which Indian troops suffered casualties. In April, five Indian peacekeepers were killed in an ambush in South Sudan.
The year also saw a crucial meeting between India and Pakistan on the sidelines of the annual UN General Assembly. Prime Minister Manmohan Singh and his Pakistani counterpart Nawaz Sharif met for the first time and discussed ways to normalise bilateral ties, in the grim backdrop of India's concerns over continued terrorism emanating from Pakistan.
The call for urgent UNSC reforms was reiterated by Prime Minister Singh when he addressed the annual General Assembly.
Indian envoy to the UN Asoke Mukerji said getting a permanent seat at the Security Council is a "top priority" for India and the Council needs to be reformed in such a way that India becomes a permanent member of a reformed Council.