UN Secretary General Ban Ki-moon visits an Ebola medical unit on December 19, 2014, in the Liberian capital Monrovia, during his tour to west African countries hit by the Ebola outbreak

The UN Climate Change Conference in Lima, Peru, in 2014. Campaigning for awareness of climate change and how to deal with it remains one of the most important UN tasks

Phumzile Mlambo-Ngcuka, Executive Director of the United Nations Entity for Gender Equality and the Empowerment of Women, speaks at the opening ceremony of a conference on gender equality on February 27, 2015. She is former vice president of South Africa

Chinese peacekeepers in Lebanon receive medals for their work

UN peacekeepers distribute boxes of food to refugees in South Sudan

In the seven decades of its existence, the United Nations has won admiration for its roles such as keeping the peace and delivering humanitarian assistance in conflict-hit countries.