People hold 'Esteladas' (Catalan pro-independence flag) during a protest at the entrance of Catalonia's regional government economy headquarters in Barcelona on September 20, 2017. Thousands took to the streets of Barcelona as Spanish police detained 13 Catalan government officials in a crackdown ahead of an independence referendum which Madrid says is illegal. With tensions mounting, separatist organisations called for more people to protest as leaders in the northeastern region pressed ahead with preparations for the October 1 vote despite Madrid's ban and a court ruling deeming it unconstitutional. / AFP PHOTO / LLUIS GENE