Venice even during the day when loaded with tourists is a maze of places unencumbered by tourists. I had loads of fun wandering around there, getting lost, discovering random small plazas, etc.
Is Barcelona like this at all or has the whole city been inundated with tourists?
Once we get near the peak we find an... amusement park!? And then just a bit further up finally the church, which is best from a distance, but had really great 360 views of everything else. All stoke, 0 tourists.
Last time I went, I visited those places, but I stayed in a tiny hotel in the gothic quarter and walked from there to Park Guell instead of using the tube, stopping to get ice cream or coffee, letting my four year old play on the park and so on. Step away, slow down and enjoy it.
I stayed in Bletchley Park this weekend to see the both the code breaking museum and the computer history museum. It was amazing. There was hardly anyone else in the computer history museum while I visited. I was able to talk with the guys who restore the computer equipment and spent some time listening to the hams in the national radio centre talk about the hobby. The few other people seeing the museums were deeply into it, trying out the codebreaking challenges or asking for nuances on how they were able to break Enigma. I felt like I was with kindred spirits and I had a helluva time.