COP21 is a series of climate change talks between various countries in Paris from 30 November to 11 December.
195 nations will come together to achieve one vitally important goal, to create a legally binding pact to keep global warming below 2°C. This, according to most scientists, is the critical threshold for global warming.
Previous high-profile climate change talks have failed, but there is real hope that success can be achieved this time. The main reason being that two of the world's biggest polluters, China and the United States, will be at the table ready to work towards an agreement.
If no deal is reached, the consequences could be grave. A warming climate could see countries disappear, increased cases of wildfire, drought and flash floods across the globe, and put 30% of animals at risk of extinction.