The worst rioting in decades may be over but calm has by no means returned to Greece.Athens has seen a 10th day of protests triggered by the police shooting of a teenager. Stones and firebombs were thrown as youths clashed with security forces. The scale of the demonstrations has tailed off sharply in recent days. But, with rallies called for later this week to denounce the policies of the conservative government, tension remains high. Students gathered outside the central police station in the capital to protest over the death of the 15-year-old. With the disturbances feeding on anger over low wages and unemployment, IMF boss Dominique Strauss-Kahn is warning that social unrest could spread, unless the global financial sector shares wealth more evenly.