Barcelona is third city in Europe by tourist visits (right after Paris and London). One can easily spot it by tourist groups around. It should be a nightmare in summer.
There is not as much Catalan flags as in Girona, still one can easily spot it. Though sometimes there are also Spanish flags. Som Catalan people believe their flag is the oldest in Europe, though there is no any proof of it. Who needs it anyway? (:
According to legend the flag appeared back in time when Charles The Bald drew four stripes by Blood of Wilfred the Hairy (the last count of Barcelona) on Wilfred's gold shield right before he died (French King put his finger in Wilfred's wound which Wilfred got during Barcelona defence from Moors in 897). The legend was extremely popular, however it turned out that Charles the Bald died around 20 years before the battle. However the legend is still alive.
The variation of flag with white star appeared after Cuba got independence from Spain. Star means freedom and remains Cuba success. There is still hope.
Streets in the old city are quite narrow, though it doesn't make any difficult for tourists and locals to walk there. Even cars can more or less freely move on these streets.
Big streets are a bit unusual: houses corners are cut. I've never seen something like this before. Freed space is used for parking or garbage containers. Maybe it's a good idea to find the space this way for the city, but as pedestrian I find it extremely inconvenient. To cross the street on a light signal I always had to make a small round instead of straight line trajectory.
Right on the streets grow mandarin trees. In the end of January right in the middle of street a lot of mandarin trees with mandarins. Hilarious.
It's really good here with fruits. There are so many small shops with fresh fruits and you can easily taste it that it's fresh (not being delivered from a long distance for months). Especially oranges, mandarins and diospyros.
It's also cool here with shops. It's one of European cities where quite a number of shops work 24/7. In central part of the city it's everywhere. Well, some stuff is a bit more expensive there than in normal network markets, but for fruits such shops are just perfect. It's fresh, good quality and cheap.
Though as in any tourist popular city there are a lot of beggars and sellers of useless stuff (like umbrellas and selfie-sticks). In the beginning it might worry a bit, fortunately after a while one just doesn't mention it.
Street musicians here are absolutely fantastic. That was the first time I saw musicians with their own full-size piano. They really move it for their performance!
I also saw here real circus on wheels. Like in cinema.
Souvenir shops surprised me. Catalan people has strange tradition to make a figurine depicted in the act of defecation for Christmas. Then they hide it and seek. Though it's not enough just to find it, one has then put it that way everybody will easily see it throughout the year. According to belief this will bring to owner luck. So it's possible to buy this figure is souvenir shop (though not any shop). Just 25 euro per piece. I was not ready for that sort of buy (:
Barcelona is a nice city. It's Europe, but a bit different Europe, with some kind of Arab east colour.