Query: What place had police experience violent problems with protesters?
Context: On March 30, 2008 in Athens, during ceremonies marking the handing over of the torch from Greek officials to organizers of the Beijing games, demonstrators shouted 'Free Tibet' and unfurled banners; some 10 of the 15 protesters were taken into police detention. After the hand-off, protests continued internationally, with particularly violent confrontations with police in Nepal.