A great city.
Park Guell is free and great.
Montjuc cable car + castle (there is a museum with some history of the Spanish Civil War).
Barri Gotik (old quarter - fun walking). Be sure to get some churros y chocolate - a famous Barca treat.
Walking the Ramblas - there will be great restaurants. Order tapas. The pan con tomate (tomato bread) is typically served, but ask for it if they don’t serve it right away.
Note: You can only get your check by asking for it for your waiter.
There are the typical attractions - great beaches, a zoo, science museum, etc. I’m sure they are all fine. When I took my three boys, my wife and I walked with them relentlessly - so much boy energy to burn off.
Mugging is fairly uncommon, but beware pickpockets.
When I visited, I stayed in the southern part of the Gracia neighborhood (near Eixample). Felt safe and a good place for walking - even with wide and busy streets. The metro system is safe, extensive and reliable.
Edit: Re-read the original message. My kids were pre-teen when we visited, but all the recs still work. Maybe switch out the churros for some sangria.
