You can do a lot of things in Barcelona. I recommend you to take a walk around the Gothic Quarter and visit the Ramblas. You can also take the cable car to Montju?c and see the beautiful views of Barcelona from up there. You should definitely go to the Tibidabo too. Try to visit the "Sagrada Familia" or at least contemplate it from outside. Park Güell is worth a visit too and you should go to "Casa Milà" and "Casa Batlló" (You can enter it if you want to but it's kind of expensive). The colombus statue is kind of cool too. I also recommend you to take the "Bus turístic" if you don't feel like walking or if it's too hot because it's a good way to see the main attractions even though it's kind of expensive (I recommend you to use the metro to get around because it's pretty good). Have fun in Barcelona and be careful with the pickpockets!
There's so much to do in Barcelona!
1) the parks are really amazing―Gaudi's Parc Güell is so bizarre and interesting, sortof Dr. Seuss-esque (also has some great views from the top), Parc de la Ciutadella is huge and old, with great fountains, a fortress on top of the hill, and the Hivernacle is a 19th century glass greenhouse and super cool; Parc d'Espanya Industrial is really interesting, with cool sculptures and not like any other park I've ever seen. And there's plenty more. Check out this article http://www.mypremiumeurope.com/travel-ne...
2) There's plenty to do nearby, too, so I'd plan for a daytrip at least once. Sitges beach is super nice. or Montserrat (touristy but really cool). http://www.mypremiumeurope.com/travel-ne...
3) Depending on when you're going, Barcelona has some of the most exciting festivals and parties in the world. From the fire festival Feast of Sant Joan to some amazing concerts.
4) Eat and drink! Spanish/catalonian food is delicious and there are some amazing restaurants at every price level. And the bars and clubs are like nowhere else.
Parc Güell by Gaudi
You should also check out the Nou Camp. Amazing stadium
La sagrada familia
what are the must-see attractions in barcelona? no museums! thanks