Berlin ? Anti-capitalist protesters set cars on fire and hurled rocks and bottles at police, turning Germany into a flashpoint on a day designated for workers but marked worldwide by rallies for a host of causes.

Police in Berlin turned water cannons on masked youths, who went on the rampage as thousands of authorized demonstrators converged on the city’s gritty Kreuzberg district, the center of May Day clashes for the last 15 years. The protesters, self-described anarchists, whooped and screamed as police chased them through streets to one of the district’s main squares.

Left-wing protesters trample a Mercedes during violent clashes with police at a May Day demonstration in Berlin. Anti-capitalist protesters set cars on fire and hurled rocks and bottles at police.

Germans also rallied against the homegrown extreme right in several cities including Berlin, where some 800 supporters of the fringe National Democratic Party marched under heavy police guard in a suburb and were heckled by counter-demonstrators shouting “Nazis out.”

In many countries, the holiday known in most of the world as a day for laborers was not all about the worker.

In France, more than 1 million people in Paris and other cities turned out to demonstrate against far-right presidential candidate Jean-Marie Le Pen.

In London, about 7,000 people marched to Trafalgar Square shouting slogans and carrying banners against everything from global warming to right-wing extremism. An effigy of President Bush was burned to applause.

Protesters in Greece and Turkey proclaimed solidarity with the Palestinians in their bloody struggle with Israel.

“A thousand greetings to the Palestinian resistance,” read a slogan at a rally in Istanbul, Turkey. In Athens, about 6,000 people marched to the U.S. and Israeli embassies to protest Israel’s military incursion into Palestinian areas.

In Russia, May Day served as an occasion to express nostalgia for the past as people turned out for marches carrying red banners and Soviet flags.

At least 140,000 trade union supporters, many holding pictures of Russian President Vladimir Putin, rallied in downtown Moscow, while the Communists held a separate rally.

In Zurich, police used tear gas, rubber bullets and water cannons to disperse several hundred protesters as opposing leftist and right-wing factions confronted each other in the tidy Swiss financial capital. About 100 people were detained.

In Havana, Cuban President Fidel Castro declared his country to be the world’s most democratic and called other Latin American leaders who joined a U.N. vote criticizing Cuba’s human rights record hypocritical “trash” who he said bowed to U.S. pressure.

Wearing his traditional olive green uniform and cap, Castro delivered a 50-minute speech to a sea of cheering, flag-waving government supporters cramming the Plaza of the Revolution.

In Asia, police clashed with protesters in the Philippines, Singapore and Malaysia, while elsewhere workers demonstrated peacefully for better working conditions and higher pay.

Activists in Sydney, Australia, used May Day to highlight the plight of thousands of asylum seekers kept in detention centers for up to three years while their cases are reviewed. Police on horseback charged demonstrators after 500 people blockaded offices of a company that operates five of the detention centers.

In one of the poorest corners of Europe, workers in Macedonia handed out platefuls of hearty cooked brown beans considered a laborer’s staple in the capital, Skopje, as they demonstrated for an “end to poverty.” The country has the highest jobless rate in the Balkans.