March 26 was Day 14 of El Paro Del Campo (unemployment on the farm) protest in Buenos Aires. News page: BBC Q&A: Argentina farm protests. The protest began in the countryside against President Cristina Kirchner's government which raised taxes on farm exports. This photo shows the front view of the advancing protesters. It was quite peaceful this day, though there were a few violent clashes elsewhere during this long-running protest. This group had people of all ages, including young adults carrying paper that stated Estoy con el campo (I'm with the farmers). They banged pots and pans in protests called cacerolazos.
The root causes are economic: inflation is high, there are food shortages, and indications are that the fantastic growth that Argentina has had since 2001, after they devalued their peso, is now coming to an end. And now the people in power (Kirchner present, Kirchner previous, and their well-placed supporters) are in conflict with the general populace.