This is the small mountain or hill you see in the north of the city behind Zona Alta. You will get a fantastic view of the city (much better than from Montjuic, in my opinion), and getting here is much more fun than going to Montjuic.
You start by taking the subway (actually the Renfe's Tibidabo local train) to the last stop, Avinguda Tibidabo (for example, from Placa Catalunya). From there, take the Tramvia Blau, which is an old streetcar, up Av. Tibidabo. Buy a return ticket if you don't plan on walking back--it is cheaper. Taking the streetcar may not be the most local thing to do, but well, you are a tourist!!! The road up to the funicular station is somewhat steep already, so it is not a bad idea at all to save a few steps, since there are so many other places where you can walk!
While in this old restored streetcar (very pretty itself already), you can see some very fancy houses that just seem to get bigger and fancier the higher you go. In Barcelona, traditionally, the prices for apartments and houses rise by the altitude . . .
Once you get off the streetcar, you are in a small plaza where there are a couple of restaurants and the funicular station. Buy the return ticket again and step on the brightly colored funicular for some very steep uphill climbing. The trip lasts several minutes, and if you're sitting in the "down" part of the car, you get some very great views of Barcelona--and see how steep the route is!
Up on Mount Tibidabo, you'll first see a large church and hear the bells. When we were there, it sounded as if the bells came from a tape that was not in the best working condition anymore--don't know if it was my ears or what . . . The church was quite pretty inside, but featured electric candles that you could light by inserting money in the machine--I had not seen electric ones before. Climb up the stairs for some more amazing views of Barcelona. You can take a different picture with the fun-fair equipment in the front!
There is also a fun fair with traditional carousels, etc. (the entrance was 20 euros!!!--which included use of the rides, but still . . . we did not go).
The Torre Calatrava is close by; there should be some form of transportation from the funicular. The views should be even better, but in my opinion, there are so many places for great views already that I cannot see the point in going there, too . . .