To get a bird's-eye view of the surrounding landscape, make the journey up to Parc del Mirador del Migdia. You may be able to spot some famous landmarks in the distance.
When you've finished at this Sants-Montjuïc scenic viewpoint, why not make your way to Sagrada Familia, La Rambla, and Plaça de Catalunya? They're close to Parc del Mirador del Migdia and also popular with many tourists.