It is hard to imagine, standing at the top of La Rambla, in the multicoloured swirl of half-dressed tourists, Mexican hats and Gaudí paraphernalia, that it was here in Barcelona on 19 July 1936 that the opening shots were fired in what was to become the Spanish civil war. Harder still to picture the anarchists of the CNT (Confederación Nacional del Trabajo) union running a city that is now firmly under the thumb of dour Catalan nationalists, or to believe that what is soon to be a gigantic Apple store was once the Communist party HQ and was draped with vast portraits of Lenin and Stalin.