Demonstrators gather around a fire in Lindenstrasse near the Jewish Museum during a May Day anti-capitalism protest on May 1 in Berlin, Germany. This year marks 25 years since a 1987 Berlin May Day demonstration turned violent and has been followed by clashes between participants and police on May Day in Berlin almost every year since. (Carsten Koall/Getty Images) #

A protester is detained by police during a rally for International Workers Day outside the Alameda County Court House on May 1 in Oakland, Calif. Demonstrators called for nationwide May Day strikes to protest economic inequality and political corruption. (Eric Thayer/Getty Images) #

An anti-capitalist protester from the Occupy movement lays in front of a police officer in Paternoster Square, which is adjacent to St Paul's Cathedral, their previous place of occupation on May 1 in London, England. Students, trade unionists, pensioners and activists from the anti-capitalist Occupy movement marched through the center of London before congregating and staging a demonstration in Trafalgar Square to mark May Day. (Dan Kitwood/Getty Images) #

A man carries an injured youngster during a march held in the framework of Labor Day on May 1 in Bogota, Colombia. (Felipe Caicedo/AFP/Getty Images) #

People weave in and out of one another as they wind red twine around a Maypole during a gathering of Occupy DC at Meridan Hill Park, also known as Malcolm X Park on May 1 in Washington, D.C. Organized by the Occupy DC Labor Committee, Anarchist Alliance DC Network, Industrial Workers of the World, Washington Peace Center, the Metropolitan Washington Council of the AFL-CIO and the Amalgamated Transit Union local 689, about 300 people gathered in the park to celebrate May Day, also known as International Workers Day, a celebration of the international labor movement. (Chip Somodevilla/Getty Images) #

Gabriel Sufi of Vienna, VA, and Nurhussen Ahmed (9) of Baltimore, MD, carry a flag while gathering with about 300 people for a May Day celebration at Meridan Hill Park, also known as Malcolm X Park on May 1 in Washington, D.C. (Chip Somodevilla/Getty Images) #

Ricky Evangelio protests while working his ice cream cart during a May Day march on May 1 in Chicago, IL. About 1000 people joined in the march which worked its way for about two miles from the city's West side into the Loop. (Scott Olson/Getty Images) #

A Bahraini Shiite employee, who was allegedly dismissed from his job for participating in pro-democracy protests, holds a banner during a demonstration celebrating Labor Day in the village of Muqsha, Bahrain. (AFP/Getty Images) #

Bangladeshi activists shout slogans and wave flags during a procession to mark May Day or International Workers Day in Dhaka on May 1. Activists around the world mark the day with marches demanding better working conditions, more jobs and higher wages. (Munir Uz Zaman/AFP/Getty Images) #

Militants and labor union members gather around a burning the effigy of Philippine President Benigno Aquino in Manila on May 1 as part of the May Day protests demanding higher wages and policies that would make it harder to fire workers. Aquino has said he is trying to help labor but has warned that giving too many benefits will make the country less competitive, costing more jobs. (Noel Celis/AFP/Getty Images) #

People protest during a May Day rally in the center of Barcelona on May 1. Tens of thousands took to the streets across the globe for May Day to press for workers rights amid tough economic times and to back an array of other causes. (Josep Lago/AFP/Getty Images) #

A protester shouts slogans during a demonstration in central Athens to mark the May Day celebrations. (Aris Messinis/AFP/Getty Images) #

Pakistani working women carry candles as they march for better wages and conditions during a May Day rally in Karachi on May 1. Pakistan has a workforce of around 56 million people among a population of 179 million, according to Pakistan's official figures compiled by the Federal Bureau of Statistics. (Asif Hassan/AFP/Getty Images) #

A Trafalgar Square Heritage Warden talks with a protester from the Occupy movement after he erected a tent during a demonstration in Trafalgar Square in London on May 1. Students, trade unionists, pensioners and activists from the anti-capitalist Occupy movement marched through the center of London before congregating and staging a demonstration in Trafalgar Square to mark May Day. (Miguel Medina/AFP/Getty Images) #

A demonstrator tries to destroy a surveillance camera during a march held in the framework of Labor Day on May 1 in Medellin, Colombia. (Raul Arboleda/AFP/Getty Images) #

A protester gets sprayed by a water canon during a May Day march in Santiago, Chile on May 1. Clashes with security forces and riots marred the rally to mark International Labor Day. (Luis Hidalgo/Associated Press) #

A police lieutenant swings his baton at an Occupy Wall Street activists on May 1 in New York. Activists with a variety of causes spread out over New York City Tuesday on International Workers Day, or May Day, with Occupy Wall Street members leading a charge against financial institutions. (Mary Altaffer/Associated Press) #

A supporter holds up a framed picture of Venezuela's President Hugo Chavez during a May Day march in Caracas, Venezuela on May 1. Venezuelan workers commemorated May Day with two separate marches, one organized by supporters of Chavez and the other by his opponents. (Ariana Cubillos/Associated Press) #

Demonstrators burn an effigy of Bolivia's President Evo Morales with a sign that reads "Careful, this brute is on the loose," during a May Day march in La Paz, Bolivia. Morales announced Tuesday his government is completing the nationalization of the country's electricity industry by taking over its electrical grid from a Spanish-owned company. (Juan Karita/Associated) #

A Bolivian miner looks out of his car, in front of a police line, during May Day celebrations in La Paz. President Evo Morales announced on May Day that Bolivia is nationalizing the local unit TDE of Spain's Red Electrica, citing the company's lack of investment in the country as the reason. The sign on the car reads, "Long live May Day. Down with changes in the labor law." (Reuters) #

Riot policemen stand guard after getting splattered by paintballs from student protesters during clashes on International Workers Day, or May Day, at the central square of Bogota on May 1. (Jose Miguel Gomez/Reuters) #

A man chants slogans during a May Day march in Revolution Square in Havana, Cuba. (Javier Galeano/Associated Press) #

Indonesian workers shout slogans during a rally to mark May Day in Jakarta, Indonesia, on May 1. Thousands of Indonesian workers staged the rally demanding the government to raise minimum wage and reject outsourcing. (Dita Alangkara/Associated Press) #

A worker shouts slogans during a rally to mark May Day in Jakarta, Indonesia on May 1. Thousands of Indonesian workers staged the rally demanding the government to raise minimum wage and reject outsourcing. (Achmad Ibrahim/Associated Press) #

A Lebanese leftist activist holds up a hammer and sickle, a symbol of communism, during a demonstration to mark Labor Day, or May Day, in Beirut on May 1. (Sharif Karim/Reuters) #

A police officer uses mace on a protester in front of an American Apparel Inc. store during an Occupy Seattle May Day rally and anti-capitalist march in Seattle on May 1. (Stuart Isett/Bloomberg) #

A demonstrator from the Occupy London movement offers a flower to a commuter during a protest inside London Liverpool Street train station in London, U.K., on May 1. Occupy Wall Street demonstrators, whose anti-greed message spread worldwide during an eight-week encampment in Lower Manhattan last year, planned marches across the globe calling attention to what they say are abuses of power and wealth. (Chris Ratcliffe/Bloomberg) #

Protestors raise their fists while singing "the Internationale" during a labor demonstration on May Day in Madrid, Spain, on May 1. Spain is the crucial front in Europe's battle to contain its economic crisis. (Angel Navarrete/Bloomberg) #

A homeless person sleeps among placards before the May Day workers march in Lisbon on May 1. The placards read in Portuguese: "Fear", "Danger", "Steps from the Abyss" and "Full of Rage". The march was marked by protests against economic austerity measures and labor law reforms, that included cut holiday entitlement, more flexible working hours and cut compensation for layoffs, that have been enacting by the Portuguese government in return to a 78 billion euro ($112 billion) bailout received in 2011. (Francisco Seco/Associated Press) #

Demonstrators hold red umbrellas during a May Day protest in Lisbon, Portugal on May 1. (Rafael Marchante/Reuters) #

An activist of Sri Lanka's Marxist political party, People's Liberation Front, drinks water from a bottle as a billboard of Communist leaders from left, Vladimir Lenin, Karl Marx and Friedrich Engels are displayed in the background during a street march to celebrate international Labor Day known as May Day in Colombo, Sri Lanka. May Day moved beyond its roots as an international workers holiday to a day of international protest Tuesday, with rallies throughout Asia demanding wage increases and marches planned across Europe over government-imposed austerity measures. (Gemunu Amarasinghe/Associated Press) #

A communist supporter attends a rally on International Workers Day, or Labor Day, in central Kiev on May 1. The flag reads, "Gaisinsky region". (Gleb Garanich/Reuters) #

A protester with her hands chained makes a V-sign as she demands freedom of speech during a May Day rally in central Ankara, Turkey on May 1. (Umit Bektas/Reuters) #

A protestor wearing a Guy Fawkes mask carries a sign during May Day demonstrations in Santa Monica, Calif. on May 1. Occupy Wall Street sought to breathe fresh life into the movement that sparked a wave of nationwide protests against economic injustice eight months ago with May Day events across the United States on Tuesday and a call for a general strike that went unheeded. (Lucy Nicholson/Reuters) #

A medic wearing a gas mask is seen during May Day demonstrations in Los Angeles, Calif. on May 1. (Jason Redmond/Reuters) #

Protesters take part in a May Day demonstration in Chicago on May 1. (John Gress/Reuters) #

A Venezuelan worker dressed as President Hugo Chavez waves the national flag during a May Day parade to celebrate the new labor law promulgated by Chavez, in Caracas on May 1. (Jorge Silva/Reuters) #

An Occupy protester gives a gesture in front of a downtown Miami Bank of America building on May 1 as part of the May Day protests. Activists across the United States joined the worldwide May Day protests on Tuesday, with Occupy Wall Street members in several cities leading demonstrations against major financial institutions. (J Pat Carter/Associated Press) #