This article describes simple experiments that showthat honeybees estimate the distance they have flown, by means of ‘opticflow’, i.e., the extent of image motion experienced by theireyes. The estimated distance is then communicated to thebees at home through the tempo of their dance (number ofdance circuits in 15 s) or the duration of the waggle phase ineach circuit. The experiments also provide strong evidenceagainst the previously held view that distance is estimatedby the amount of energy consumed during the flight. Theseexperiments illustrate how cutting-edge research is possiblewith little or no facilities, equipment or money, by asking theright questions, optimizing the design of the experiments andregarding previously fashionable theories with an appropriatedegree of scepticism.