La concentració va ser convocada per Podemos, partit polític fundat fa tan sols un any i que en aquest temps ha aconseguit cinc escons al Parlament Europeu i posicionar-se com a possible guanyador de les eleccions generals del 2016 a Espanya.
The rally was called by Podemos, a political party founded just one year ago that nevertheless won five seats in the European Parliament, positioning itself as a potential winner of the Spanish general elections in 2016.