It always rains in november

Where: Grotta Azzurra, Capri, Italy.
What: The official color of water is blue. This is not always obvious, the primary color of the Seine in Paris seems to be green, while most canals and rivers in the Netherlands are some kind of brownish. In small quantities there’s no color at all. The Grotta Azzurra, however, is true blue. The cave has two entrances, one under water for the sunlight that appears to light the water from below, and the other on the surface. The latter one is rather small, making entrance into the cave possible only by rowing boat (with guide) or by swimming.