El Desafío is the global title of an ambitious series of documentaries about the great events in the recent history of Spain, the most shocking and with international projection, whose traces are still appreciated today. The first season covered the fifty years of the State's struggle against the terrorist organization ETA, from its first assassination, in 1968, to the end of its armed war in 2011 and its subsequent dissolution. The second season has focused on a much more limited historical moment in time: the jihadist attacks carried out in Madrid on March 11, 2004. In both cases, events that have left deep wounds in Spanish society.