TOPSHOT - University students hold Catalan pro-independence 'Estelada' flag during a demonstration against the position of the Spanish government on the referendum on self-determination  in Catalonia during a university students strike on September 28, 2017 in Barcelona. - Thousands of students went on strike to the streets of Barcelona today as part of the "permanent mobilization" of the Catalan separatists, three days ahead of the referendum on independence banned by Spanish justice. (Photo by Josep LAGO / AFP) (Photo by JOSEP LAGO/AFP via Getty Images)