Photos: May Day protests around the world

Police officers in plain clothes form a cordon as demonstrators, unseen, march past during a protest in Barcelona, Spain, Tuesday, May 1, 2012. Tens of thousands of workers marked May Day in European cities Tuesday with a mix of anger and gloom over austerity measures imposed by leaders trying to contain the eurozone's intractable debt crisis. Spanish Prime Minister Mariano Rajoy is trying desperately to cut a bloated deficit, restore investor confidence in Spain's public finances, lower the 24.4 jobless rate, and fend off fears it will join Greece, Ireland and Portugal in needing a bailout. (AP Photo/Emilio Morenatti)