Reports say as many as 60,000 people are protesting in Greece in response to new austerity measures that increase sales taxes to 23 percent, reduce pensions and wages and make it easier for government workers to be fired. Excise taxes on tobacco, alcohol and fuel will also be raised.
The austerity measures, which are meant to save about $40 billion are a condition for a Greek bailout announced Sunday by the European Union and the IMF.
Those moves haven't gone over well with the Greek people, to say the least.
Rioters used sledge hammers to smash the glass fronts of more than a dozen shops, banks, jewelers and a cinema.
Youths also set fire to rubbish bins and a car, smashed bus stops, and chopped blocks off marble balustrades and building facades to use as projectiles.
Organisers said some 60,000 people took part in the protest. But an unofficial police estimate set the crowd at around 20,000 - including those that took part in a separate, peaceful march earlier Thursday. Police do not issue official crowd estimates for demonstrations.