Easier than going all the way to Camp Nou in Les Corts, Mare magnum is a huge shopping centre near the IMAX cinema. The Aquarium is worth a visit in any case.

Mare Magnum is on the port it is more a tourist attraction than a shopping centre, shops there are expensive, as well as a huge cinema (in Spanish) They have a Mini Golf course on the roof, A Irish bar, Restaurants and lots of night clubs at night.
Around the corner you will find Port Vell and the Aquarium.