I missed out on going to Seville 5 years ago because Thomas cook double booked! But wish i had as it is everything Barcelona is but less of a metropolis as far as i understand. When we went to barcelona it was like a hot liverpool, though that was in 1974
Barcelona is amazing...but very hot at this time of year. If you do go, I can recommend the tourist bus routes, which allow you to hop on and off where you like throughout the day xx