Snorkelling is like cooking slow food. If you take your time and don't rush, you get the most fantastic rewards. The sea is warm, the sky is blue, and you enter a world of unimaginable beauty - huge brain-shaped corals, multicoloured fish, miniature jewels of iridescence lying on the ocean floor. You can watch everything, from a cruising Titan triggerfish to a tiny goby sharing its hole with a blind digger shrimp. You hear a noise - it's a shoal of small fish leaping into the air to escape a barracuda. You look down, and you see a green turtle ripping into sandstone with its beak to get at the sea grass below.