Corcovado, the "most biologically intense place on Earth" (National Geographic). This picture shows the coastal strip, where dense rain forest meets the Pacific Ocean. The forest grows taller, wider and more remote the more one hikes inland.
For those adventurous enough to explore the depths of Corcovado National Park individually, Puerto Jimenez is the place to start. From here one can obtain permits to camp in one of the ranger stations within the park, get a collectivo to Carate and start an unforgetable trek.
The park itself offers without a doubt the most impressive rainforest experience in Central America and is because of its remoteness and location about 10 hours south of San Jose not as overvisited as the typical National Parks on the 'gringo path' such as Manuel Antonio or Monteverde.
Other than trekking for 9 hours to the central ranger station people can get there on a guided tour (book early) by boat from Drake's bay or by a little airplane from Golfito. The central ranger station is the tourist hotstop and hosts scientists, rangers, tour groups, guides and individual campers. From here it is, where one heads to Rio Sirena to watch out for crocodiles, bull sharks, taipirs and coatis, just to name a few of them.
I was backpacking in this country for about 4 weeks, and if one ask me what to see in Costa Rica during a trip, my answer is clear: This place! I did a three day loop from the ranger station in the north, Los Patos to La Sirena and then to Carate.