Despite what management gurus may say, it is not always necessary for a group to have a leader. Acting almost like a single body, a group may very well do without one.Indeed, there are plenty of examples in nature. Shoals of sardines swim, tightly bunched, in the same direction and are quick to avoid predators. Flocks of starlings swirl, displaying astounding co-ordination and speed. At a much smaller scale, bacteria form colonies characterised by collective behaviour. Even the skeleton of a single cell is the result of fascinating self-organisation. Yet we still understand very little of such behaviour, ranging from simply moving forward in a group to whirling bodies and spontaneous congregation. For the first time a research team has proposed a particularly spectacular, controlled experiment to improve our grasp of such collective movement.