COP21, also known as the 2015 United Nations Climate Change Conference, took place in Paris, France. It brought together representatives from nearly 200 countries to negotiate a global agreement aimed at combating climate change. The main goal was to limit global warming to well below 2 degrees Celsius above pre-industrial levels. The conference resulted in the Paris Agreement, a landmark accord that encourages countries to set their own climate action plans, known as Nationally Determined Contributions (NDCs). This agreement marked a significant step in international efforts to address climate change and promote sustainable development.