The Challenge: ETA is a 2020 English-language Documentary show. An eight-episode documentary series about the fight of Spanish military police, the Guardia Civil, against the terrorist group for the independence of the Basque Country known as ETA. The challenge: eta stars José Antonio Zarzalejos in the lead role along with Iñaki Gabilondo, José Luis Rodríguez Zapatero, Mariano Rajoy, Juan Carlos De Borbón and Arnaldo Otegi in supporting roles. An eight-episode documentary series about the fight of Spanish military police, the Guardia Civil, against the terrorist group for the independence of the Basque Country known as ETA.