Demonstrators around the globe observed May Day this past weekend with protests and mass gatherings, including a few that turned violent. The day has become an occasion for a wide range of agendas, from promoting rights for immigrant workers, to a traditional nod for International Workers' Day, to a call for a revival of communism, to a celebration of spring. Here is a collection of images focused on how workers, unions, socialist groups and others marked the day. -- Lloyd Young 39 photos total