This report analyses the international climate negotiations that took place at the 16th Conference of the Parties to the UNFCCC held in Cancún in December 2010. It discusses the negotiation process on the following central "building blocks" of the negotiations: the legal form of a future agreement, mitigation, measuring, reporting and verification, adaptation, finance, technology and reducing emissions from deforestation and forest degradation (REDD). The report discusses the results in detail and concludes with an outlook on how the challenges ahead could be overcome.