Maremagnum shopping mall Barcelona. Open all week including Sundays. Maremagnum is a modern shopping mall with many brand names shops, restaurants and bars. It is located at the bottom end of La Rambla walking street in the Port Vell harbour of Barcelona. Maremagnum’s top floor has a nice open-air terrace surrounded by a selection of twenty new gourmet restaurants that offer good quality dining with harbour and all the city and harbour views.