Barcelona is in the Spanish state of Catalonia, which has a very vibrant and growing independence movement. The Catalonia flag has red and yellow stripes on it, while the Catalonia independence movement has the same red and yellow stripes, but also with a blue triangle and a white star (see pics below).
While I was in Catalonia, I saw countless flags flying from people’s balconies. Among them were the flag of Barcelona (the blue and yellow flags, pictured below), Greece, and even Palestine. However, there was one flag that dominated the rest in sheer numbers: the Catalonian independence flag.
Many Catalonians are fed up with corruption and stagnation from Madrid, the capital of Spain, as well as feeling under represented. They feel that Catalonia has the strongest economy in Spain and that the rest of the country is simply siphoning their prosperity.
For more information about the independence movement in Spain, check out these two news stories: