Tortuguero National Park
Tortuguero National Park is a fantastic natural park and a must-see if you're in Costa Rica. If something surprises you at this park it'll be the diversity of animals, birds and the famous nesting turtles (tortugas). To get to the park you can only get there by water, there's no way to get to it by land. So the entry took a boat gave us a ride around the park all morning. My recommendation is to stay an extra day to sleep because that way at night you can see the spawning (at about 3:00 in the evening) and can stay in the lodges (if you have budget for it) or the cabins, which are much cheaper.