One of the very few bioluminescent bays in the world where you are allowed to swim, and that changes everything. You go over…One of the very few bioluminescent bays in the world where you are allowed to swim, and that changes everything. You go over the side into black water and your entire body outlines in blue-white light as you move. Boat wakes glow like neon. The glow comes from dinoflagellates thriving where fresh river water meets warm salt water in a shallow, sheltered lagoon, a combination rare enough that only a handful of permanently glowing bays exist. Known locally for generations before it became a tourist attraction in the mid-20th century. Anchorage: Shallow lagoon where the Martha Brae river meets the sea; small-boat access. Falmouth harbour nearby. Hazards: No site-specific hazards noted, brief normally. Meer