Go and see the Coke Lagoon, where you can have a nice bath. It's called like that because the water has the coke colour. It's because of the vegetation that there is inside the lagoon which gives the water the coke colour. It's situated south of Pipa and it's usually in the itinerary when you do a buggy tour.
At the " ECOLOGICAL SANCTUARY " site,you can see the swamps between the dunes,it's a very recomended trip,watch the vegetation here,getting green as it receives sweet water from the soil ( diferent from the vegetation you find along the coast).