The Barcelona Cathedral is a typical gothic cathedral with its tall detailed columns stretching up to the sky, spreading outwards like upside down tree routes to form the vaulted ceiling. When we were in Barcelona I visited the cathedral many times. Partly because it was so awe-inspiring to stand under that roof, and partly because it was about 100m from our apartment. Every hour we heard the bells of the cathedral beat out the time, and after a while it became almost reassuring to hear the bells as I drifted off to sleep after spending an evening wondering around the gothic quarter of Barcelona.
Montjuic Castle is at the top of a 17th century hill. The view from the castle is amazing, and it is free to visit. Although you either need to pay to take the cable car to the top, or prepare yourself for a long uphill walk!