Corcovado National Park

Costa Rica's wildest lowland forest, on the remote Osa Peninsula, where long beaches meet unbroken rainforest and the wildlife list runs to some 6,000 insects, 140 mammals and 367 birds. Macaws, whales offshore and the chance of something rarer on the trail are why people make the effort. Every visitor must enter with an authorized guide, which keeps the park safer and far better explained. The best way in is a night or two in the bunks at Sirena ranger station, reached by boat, light plane or a long, hot beach hike; the beds are basic and need booking well ahead. Day trips from Drake Bay or Puerto Jiménez are easier but see less.