During their 0-1 defeat to Barcelona on Saturday at Cornellà-El Prat, Espanyol fans unfurled a "Welcome to Barcelona" banner, which referred to their crosstown rivals as "Tourists". I didn't know that fans of Los Periquitos see themselves as the "local" team of the city, in similar fashion to how Manchester City fans often see United as a club supported by provincial day-trippers, Irish and Scandinavians.
Barça certainly have a massive following outside the city, but the frequency and intensity of such support dissipates quickly outside of their Catalan heartland. For example, I can't imagine Villarreal fans at Camp Nou - if they bring any - singing "We'll race you back to Castellón de la Plana". Maybe they do.
[Reddit]