Manú National Park is a biosphere reserve located in Madre de Dios and Paucartambo, Cuzco. Before becoming an area protected by the Peruvian government, the Manú National Park was conserved thanks to its inaccessibility. The park remains fairly inaccessible by road to this day. In 1977, UNESCO recognised it as a Reserve of Biosphere and in 1987, it was pronounced a World Heritage Site. It is the largest National Park in Peru, covering an area of 15,328 km². The park protects all of the ecological zones that exist in the Amazon Basin, covering an altitudinal gradient between 150 and 4200 meters above sea level. Because of this topographical range, it holds one of highes biodiversity of any park in the world. Overall, more than 15,000 species of plants are found in Manú, and up to 250 varieties of trees have been found in a single hectare. The reserve is a destination for birdwatchers from all over the world, as it is home to over 800 species of birds, nearly the total for all of North America.