Natural World Heritage sites are internationally recognized as having the highest global conservation significance and include iconic places such as the Serengeti, Great Barrier Reef and the Galapagos Islands. These renowned sites offer crucial insight into the successes and challenges on the frontlines of conservation, but only about half of the natural sites have been regularly monitored through the main monitoring mechanisms of the World Heritage Convention. The IUCN World Heritage Outlook monitoring system, which consists of Conservation Outlook Assessments, complements the Conventions monitoring mechanisms and assesses all World Heritage sites in recognition of their natural "Outstanding Universal Value." This report describes the methodology for the IUCN World Heritage Outlook, reviews the rating system applied and then summarizes the first set of global results. We hope the IUCN World Heritage Outlook will serve as a dynamic new tool to assist in celebrating best practice in World Heritage sites and in helping to address the management challenges in some of the most iconic places on Earth.