Read more about May Day in Cuba here.
Dmitry Kostyukov / AFP - Getty Images
A woman greets Russian communist supporters from a window with a red cloth during the traditional May Day rally in central Moscow on May 1. May Day traditionally celebrates the rights of the proletariat in the former Soviet Union. Crowds waving balloons and blue or red flags gathered in cities from the Pacific port of Vladivostok to Moscow in carefully-choreographed rallies reminiscent of the Soviet era when May 1 was one of the most venerable holidays celebrating international socialism.
Pawel Kopczynski / Reuters
Riot policemen stand beside fire flares as they clash with left-wing protestors during May Day demonstrations in the Kreuzberg district of Berlin, May 1.
Javier Galeano / AP
Cuban soldiers bearing their national flag march in the May Day parade at Revolution Square in Havana, Cuba, May 1. The demonstration is being touted as a massive show of support for economic changes recently approved by the Communist Party - even though the people holding placards and shouting slogans haven't seen the details yet.
Kostas Tsironis / AP
A man walks next a tied up ship at the port of Piraeus, near Athens, on Sunday, May 1, during a 24-hour port strike. Rail services in Greece, including the Athens suburban railway were suspended for 24 hours. Protesters gathered in central Athens and other Greek cities for May Day rallies to protest against the austere measures needed to secure rescue loans for near-bankrupt Greece.