On the east side there are remnants of Propylea. By far the main attraction of the island is the Blue Cave, on the SE side, named by the inhabitants phokialí (Greek for seal's refuge). Being 40-50 m long, 25-30 m wide, and 20-25 m high, it is much larger than the world famous Grotta Azzurra on Capri, Italy. The light of the Sun, refracted through the first layers of sea water, is reflected in the interior of the Grotto, producing the well-known blue colour, and other effects, like the silvery appearance of submerged bodies. The Cave can be visited only by boat and, since the entrance is barely one meter high above the sea level, only under calm sea condition: the best time of the day to visit it, is early in the morning, when the Sun is still low.