The Bosawás Biosphere Reserve in the northern part of state Jinotega (border with Honduras), Nicaragua is a hilly tropical forest designated in 1997 as a UNESCO biosphere reserve. At approximately 20,000 km² (2 million hectares) in size, the reserve (i.e. nucleus plus buffer zone) comprises about 15% of the nation's total land area making together with the biosphere of the banana river in Honduras that geographically is a single jungle only that is divided by land borders it the second largest rainforest in the Western Hemisphere, after the Amazon in Brazil. Bosawás is largely unexplored, and is extremely rich in biodiversity.