Grotta del Bue Marino (Cave of the Monk Seal) is the largest, most famous and beautiful cave on the Filicudi Island. The cave is 20 meters high, 30 meters wide and 20 deep, accessible by small boats and by swimming. In the bottom of the cave is a small pebble beach. In past it was a refuge for the Monk seal. Now this magical corner of the coast is famous for the play of light effects generated with shades of blue, green, grey and yellow – this is a small corner of paradise.