In the south of the island is one of the most impressive natural monuments of the Mediterranean.

In the "blue cave" of Kastelorizo live seals, which are normally invisible to visitors. That is why it is called "Fokiali" or "Cave of Parasta". Apart from the seals, the cave is also home to thousands of wild pigeons, while at its bottom there are unique and rare species of fish.

The cave is 35 meters high, 40 meters wide and the length of the cave inside is 75 meters. However, its entrance between the rocks is so small that it gives no clue as to what will follow upon entering. The towering dome of the cave is covered with white stalactites, which are one of the rarest geological phenomena on earth. When the sun's rays penetrate the cave, the stalactites take on unique colors, while the cave's water turns a bright blue color, inspiring awe in the visitor.

The best time to enjoy the magnificent spectacle is in the morning. Visiting the cave is only by boat and of course in good weather, as its entrance can only accommodate small boats.

In case of wind, the entrance is closed and the cave is not accessible. Apart from the famous Blue Cave, there are four other caves of rare geological beauty in Kastelorizo, Fotsaliki, Kolones, the cave of Arnaoutis and Katrantzis.