Greece's public sector workers have gone on strike in protest at the government's austerity measures.
Many of the protesters feel they are being made to pay for the mistakes of others.
The European Union is a focus of some protesters' anger.
Others place the blame closer to home, targeting politicians including Prime Minister George Papandreou.
Transport links have been paralysed by the strikes.
Greek airspace is closed to all flights, as vital air traffic control staff have walked out.
Many passengers are stranded, waiting for services to resume.
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