Results are presented from a study of the structure of high energy hadronic events recorded by the L3 detector at √s≥192 GeV. The distributions of several event shape variables are compared to resumed O(αs2)QCD calculations. We determine the strong coupling constant at three average centre-of-mass energies: 194.4, 200.2 and 206.2 GeV. These measurements, combined with previous L3 measurements at lower energies, demonstrate the running of αs as expected in QCD and yield αs(mZ)=0.1227±0.0012±0.0058, where the first uncertainty is experimental and the second is theoretical.