The Blue Grotto is a popular sea cave on the coast of the Italian island of Capri. Sunlight, passing through an underwater cavity and shining through the seawater, creates a brilliant blue reflection that illuminates the entire cavern.
A small opening serves as an entrance to the cave. Visitors are ferried inside the cavern via small wooden boats manned by experienced oarsmen for a fee. To be able to fit into the tiny hole, visitors must lie on their backs in the bottom of the boats as they pass through the entranceway. Once inside, the visitors can sit upright and enjoy the beauty of the grotto. They will need to pass through the same hole to get out of the cave.