We stayed in Barcelona for 3 nights and 4 days. 
There’s a Barcelona Pass which is a 2 day Barcelona card that guides you in exploring the city. This electronic s
mart card offered free admission to many museums and attractions. A few years ago, some of the options included:
- free access on public transportation,
- the train to and from Barcelona airport,
- a panoramic tour on the shuttle boat “Las Golondrinas”,
- discounts in more than 26 museums,
- the Barcelona Zoo
- the Aquarium
- The Barcelona Walking Tours
- shops, shows, rental cars, etc Click on the link below to see the updated version of the Barcelona Card:
http://www.viator.com/tours/Barcelona/Barcelona-Card-with-Guidebook/d562-2512bcard