Hahaha... I knew that everyone would ask for Sagrada Familia Cathedral... It's amazing how everyone knows Barcelona for it, and maybe for a football club... The rest is "unknown"... 😃 They should write a book "How to Create a World-famous City Just by One Cathedral"... which isn't yet finished, btw... 😄
Is it an expensive city?
I was there only for a couple of hours so I can't say too much about it, but I think it is probably one of the most expensive cities in Spain...