Panoramic of the milky way arch in the cave of Cala Luna. Sardinia. The beach of Cala Luna, positioned within the wide Golfo di Orosei, is made up of coarse, light-coloured sand mixed with stones. Its waters are transparent and of a changing blue due to the plays of light created by the sun reflected on the seabed: a further spray of colour is offered by the green of the vegetation that hems the beach