The 4070-sq-km Parque Internacional La Amistad – by far the largest protected area in Costa Rica – is an enormous patch of green sprawling across the borders of Panama and Costa Rica (hence its Spanish name La Amistad – 'Friendship'). Standing as a testament to the possibilities of international cooperation and environmental conservation, the park was established in 1982 and declared a Unesco World Heritage site in 1990. It then became part of the greater Mesoamerican Biological Corridor, which protects a great variety of endangered habitats and animals. Its cultural importance is also significant as it includes several scattered indigenous reserves.
The largest chunk of the park is high up in the Cordillera de Talamanca, and remains virtually inaccessible. There's very little tourist infrastructure within the park, although hard-core exploration of some of the country's most rugged terrain is possible with an experienced guide.