Blue Cave
Blue Magic on Biševo (Croatia). 'Of the numerous caves around the remote limestone island of Biševo, the Blue Grotto (Modra Špilja) is the most spectacular. On a clear morning, the sun’s rays penetrate through an underwater hole in this coastal cave, bathing the interior in a mesmerising silvery-blue light. Swimming inside is a surreal must-have experience – worth a trip to this far-out island.' http://www.lonelyplanet.com/croatia