Hundreds of thousands of people angered or worried by the global economic crisis turned out for May Day rallies around the world. Most were peaceful, but some turned violent.
The worst violence occurred in Turkey and several European cities. In Germany, on course for its biggest slump since World War II, the Berlin police made 49 arrests as young demonstrators hurled missiles and set fire to cars and bins in the early hours.
About 150 far-right extremists were arrested after skinheads attacked a trade union rally in the western city of Dortmund.
Almost half a million people had earlier assembled peacefully across Germany, unions said. A group of protesters in central Berlin pelted the Finance Ministry building with brightly coloured paint bombs.
Mexican ban on May Day rallies defied
In Turkey's main cities, Istanbul and Ankara, security forces fired tear-gas and water-cannon as protesters smashed the windows of banks and shops.
Violence was also reported in Greece, Switzerland and Austria.
The police in Mexico City also clashed with around 200 protesters trying to march on the federal government's palace - despite a suspension of traditional May Day rallies by the government and unions amid a five-day lockdown triggered by the potentially deadly H1N1 swine flu.
French unions present a united front
Elsewhere, rallies were mostly peaceful, with organisers everywhere promising to highlight public anger over millions of job losses.
The leaders of France's eight main unions - presenting a united front for the first time since World War II - linked arms to lead a rally in Paris.
The CGT union claimed that 1.2 million took part in 300 marches nationwide, but the police said that only 465,000 turned out.
In Spain, where the government expects nearly one in five workers to be out of a job next year - the worst unemployment rate in Europe - tens of thousands turned out across the country.
Show of solidarity with earthquake-hit town
Leaders of the main unions in Italy held their rally at the town of L'Aquila in a show of solidarity after the devastating earthquake there last month that killed nearly 300 people.
Around 36,000 people rallied in Tokyo's Yoyogi park, demanding more welfare benefits or protesting against military spending.
In South Korea, some 8000 workers and students answered the call, and there were also rallies in Manila, Phnom Penh and Taipei.
Knives and knuckledusters in St Petersburg
About 2000 demonstrators gathered by a statue of Karl Marx in Moscow calling for a return of communism. But St Petersburg, birthplace of the 1917 Bolshevik revolution, saw about 120 far- right militants armed with knives and knuckledusters arrested.
In Cuba, President Raul Castro, decked out in a tropi-casual guayabera shirt and farmer's hat, led an estimated 500,000 people called out to march in the annual parade.