Stick a toe in the water at Balneari de la Font Picant. Weather permitting, you can go swimming or just sit back and enjoy spotting interesting birds.
You'll find this waterhole in Sant Hilari Sacalm. Once you've done everything you can at Balneari de la Font Picant, take a look at nearby Font del Pic Park, Doctor Gravalosa Park, and Celler d'en Jordi.