Children play soccer at the Father Carlos Mugica slum, also known as Villa 31 in Buenos Aires May 10, 2014. May 11 marks the 40th death anniversary of Mugica, a well-known Roman Catholic priest from a prominent family. A leader of the Movement of Priests for the Third World, Mugica was active in rallying for workers' rights in the villas (shantytowns) and social programmes for the poor before he was killed by an unidentified group. REUTERS/Enrique Marcarian (ARGENTINA - Tags: ANNIVERSARY RELIGION SPORT SOCCER)