I am not an expert in Barcelona, but I’ve been there and here’s what I’d recommend doing. I would take a Hop-On-Hop-Off bus tour. You get an overview of the city while you listen to a narrated tour on a headset. There are 2 loops in Barca-the East and West. Combined, you get an excellent overview of the city.
I took a more complete tour from Barcelona Day Tours that picked me up at my hotel and gave a guided tour of Barcelona and the monastery in Montserrat (home of the Black Madonna). I highly recommend it. We had an in-depth tour of the outside of La Sagrada Familia (Catholic Church) and then drove up the hills to Montserrat. On the way out of town, we passed several buildings designed by Gaudi (who designed La Sagrada) like Casa Batllo and La Pedrera. He has a unique style called “Modernism” where he designed every element of his structures- the wrought iron gates, the tile design, the furniture, the chandeliers, and windows. He used shapes from nature like leaves and birds. He uses arches a lot. Anyway, when most people see his work, they just think it’s cool. Gaudi’s influence is largely what makes Barca a cool place. You’ll see.
After Montserrat, we went back into the city and went into the 1992 Olympic Stadium and drove around the Montjuic (green zone) parks. We arrived at another Gaudi creation- Park Guell. It was Gaudi’s concept of a garden city where residents sought to escape from the industrial city. It features an undulating bench, green space, and a mosaic dragon statue. It requires a reservation and ticket to get in which was included in our tour. After visiting the park we were dropped off at our hotel. The tour was 8 hours and definitely worth it.
For your next day, I’d take a stroll in the Gothic Quarter. It has narrow medieval streets filled with trendy shops, bars, and restaurants. It’s like going back in time without the bad part. Next, I’d go to Mercat de la Boqueria which is a large public market off of La Rambla street which is a tourist landmark. Locals just call it La Boqueria. Then, I’d stroll down La Rambla which is a tree-lined pedestrian street that stretches all the way down to the port.
Just a warning now-- the number one place in the world for pickpockets in on La Rambla Street so be smart and be aware.
There are more things to see if your energy is up. You can get a guided tour of the inside of La Sagrada Familia. Visit Camp Nou- home of my favorite soccer team in the world-FC Barcelona with the great Messi. If you’re into art there is a Picasso and a Joan Miro museum. And at night, there is the Magic Fountain which features colored lights and a water show synchronized to music.
Now just a few more recommendations from my experience. If you like fresh seafood (I mean caught that day), go to one of the 8 Paradeta restaurants located throughout the city. Excellent and reasonable prices.
And finally, if you want a 5-star superb hotel it’s called The Majestic. The breakfast buffet is unbelievable.