Michaelmas Cay, on the Great Barrier Reef off Cairns, is 10km long reef with a sand cay. Explore the bommies, walls, swim-throughs, gullies, small caves and overhangs. See Giant clams, blue-spotted rays batfish, cleaner stations, nudibranchs, crayfish and turtle weed clumps. Schools of damsels and fusiliers dance over the coral. Standing on the beach you may experience fish "biting" at your heels - they're only trying to catch shrimp and other small animals.