May Day 2011 marches around the World [PHOTOS]

Thousands of demonstrators gathered at May Day marches around the world, which took place in cities like Istanbul, Ankara, Paris, Berlin.

In many countries, May Day is synonymous with International Workers' Day, or Labour Day, a day of political demonstrations and celebrations organised by communists, anarchists, socialists, and activist groups. The commemoration of May Day as International Workers' Day received its inspiration from the United States, going back to the 1886 Haymarket affair, when police opened fire on striking workers and 4 people were tried and then publicly hanged for their political beliefs. The corporatist U.S. successfully tried to void May Day of its symbolism for the worker rights about 50 years ago, and the United States are one of the countries where today no bigger demonstrations take place.

May Day is also a traditional holiday in many cultures. May Day is related to the Celtic festival of Beltane and the Germanic festival of Walpurgis Night. May Day falls exactly half of a year from November 1, another cross-quarter day which is also associated with various northern European festivals such as Samhain. May Day marks the end of the unfarmable winter half of the year in the Northern hemisphere, and it has traditionally been an occasion for popular and often raucous celebrations.

Here are some pictures of demonstrators around the world.