"Accessible by ferry from the main island of Puerto Rico, this secluded stretch of sand may leave you 'the only one there' and features sand derived from white coral that is described as 'unbelievably soft'; visit from December to mid-April and you might see bioluminescence at Mosquito Bay, which 'illuminates the water with electric blue light when you agitate the dormant algae.'" - Travel + Leisure Editors