Where is it: Isla de Vieques
What is it: A rare natural phenomenon, Mosquito Bay is populated with harmless microscopic organisms that glow like fireflies when they detect motion.
Why go: Nothing can prepare you for the amazing spectacle of electric blue luminescence that emanates from the water when the bay is at its brightest. The only way to experience it is to take a nighttime kayak tour and watch the dip of the oar and the wake of the boat shine. Brightness and color vary depending on conditions, so go on a new moon for best results. By all means, try to take a photo or two, but no camera can do justice to this.