International Workers' Day, also known as Labor Day in some countries, is a celebration of laborers and the working classes promoted by the international labor movement, socialists and communists, and occurs every year on May 1.
People shout slogans and wave flags during a May Day workers march in Madrid, May 1, 2016. Trade unions and other groups staged rallies around the world Sunday to mark the International Workers Day.
Russians wave flags and cheer as they walk on Red Square to mark May Day in Moscow, Russia, May 1, 2016. As in Soviet times, cheerful workers paraded across Red Square but instead of red flags with the Communist hammer and sickle, they waved the blue flag
Riot police detain a man during the traditional May Day march in Paris, France, May 1, 2016. The traditional May Day rallies are taking on greater weight this year in France as parliament is debating a bill that would allow longer working hours and let co
Cambodian garment workers hold banners during a gathering to mark May Day in Phnom Penh, Cambodia, May 1, 2016. The workers staged a rally to demand higher wages and better working conditions.