The most extraordinary feature of Vanuatu's underwater world is not just the superb visibility, warm water or easily accessible dive sites, but the incredible diversity of diving and dive sites. Amid clear warm water and abundant marine life scuba divers can experience caves, swim-throughs, walls, lava towers, fantastically elaborate wrecks, coral mazes, grottoes and overhangs. Then there are wrecks! Planes, an old square rigger sailing ship, a destroyer and of course the mightiest shipwreck in the world, the SS 'President Coolidge'.