Just outside Barcelona is the mountain, Montserrat (not to be confused with the more famous island). A short train ride makes for a great day trip up the mountain. You can choose to go all the way up by either cable car or railway, with the cable car being faster. I chose the cable car and it offered amazing views up the mountain (not for those afraid of heights). A couple of funiculars take you up even higher where you can choose various walking trails. I will freely admit to choosing one of the shorter trails because at this point in the trip, I already know that selecting a more adventurous one is something I will regret. And my shoes are wearing down to the point where traction is at a premium!