Blue Eye of Buracona is a lava tube, which is currently destroyed by the erosion of the sea. The collapsed cave has an opening to the sea and a second opening to the surface, the cave is filled with sea water connected directly with the sea. The opening allows sunlight to fall on the sea water and light thus drawing the shape of an eye. The deep blue color is reflected in water. The result is breathtaking and is a reason why this place is so popular. (from a personal photo)