There are several bioluminescent bays

There are several bioluminescent bays to visit in Puerto Rico, but Mosquito Bay, on the small island of Vieques, is your brightest choice (it even earned a nod in the Guinness Book of World Records). Bioluminescent plankton in the water light up when they’re disturbed, giving the bay an ethereal glow that intensifies around passing boats and swimmers.