we did a simple and cheaper way. we took metro blue line got off paral lel, then took funicular( we made a small mistake -we got out of metro station and tried to look for funicular station, actually the funicular station is inside metro station, you don't need to get out of metro station, just pay a bit attention to the sign, you will find it. this small mistake cost us 98 cent-carnet cost 9.8 euro for 10 rides *3 people-we had to insert our carnet ticket again).
montjuic is quite big, easy to get lost, luckily we did not. first we visit Olympic stadium( 10 min, free), outside viewing montjuic castle( saw many castle during this trip, so none of us interested in getting in another castle), had our picnic and fed the pigeons above magic fountain( good photo) then walk down to plaza de espana. total cost us lesser than 2 euro each.
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