The capital of Catalonia is full of history, architecture and art. Instead of recommending the usual places to you, I advise you to walk around and discover the city for yourself. Every neighborhood has its own soul and rituals, and the only way to discover them is to spend some time in each of them.
If your time is limited, you can stay in the very center and explore Gracia, El Raval and El Gotic (if you’re looking south, the first is on the right side of The Ramblas and the other to the left side), and El Born. If you have a whole week, though, you’ll have enough time to explore the whole city, including the neighborhoods of Sant Gervasi, Sants, La Barceloneta and Poble Nou.
In any case, if you want to visit monuments or museums, be sure to show up first thing in the morning; the admission lines can be long. Book in advance whenever possible, to avoid the crowds. And if you visit the Sagrada Familia my only advice is: have patience.
Passeig de Gràcia
This is the main street in Barcelona for shopping. It stretches for a mile and is full of (expensive) shops and restaurants; it’s also where almost all the big modernist buildings are (among the most beautiful and famous: La Casa Fuster, la Casa Ametller and La Pedrera). Don’t make the mistake of eating here, except for very late at night: prices are jacked up for tourists and the food is usually not the best.
This building needs no introduction from me; this is masterpiece of Antonin Gaudí is one of the most famous churches in the world. The new chapel is so spectacular (just the light is unbelievable) that even the locals are lining up to see it again and again. As I said before, have patience and go there early: you won’t be disappointed.
This street is so famous that it even has its own verb in Spanish: ramblejar. “Rambling” in Barcelona means to wander up and down Las Ramblas on foot—and that’s something I recommend you do at least once in your life. Las Ramblas has many attractions, like La Boqueria market and the Columbus monument, but the biggest draw is the street itself. One last thing: if you visit at night, don’t wear your camera around your neck and don’t flash your wallet; it’s a pretty safe place, but pickpockets and small-time thieves can be an issue here after dark.
This is the most historically relevant of all Barcelona’s neighborhoods. Most of the buildings here are centuries old and have no elevators; many streets are so narrow that there is a no-cars-allowed policy in the entire area. The Catalan resistance in the 1714 war is reflected in sites like El Fossar de les Moreres and El Museu del Born.
If you are a fan of history (and architecture), you must visit this neighborhood. This is where the “new Barcelona” had its beginnings in the middle of the 19th century. The municipal plan (called Cerdà) called for the creation of a large central square, so the city could build around it in a new way. The avenues here are broad, with dozens of shops and restaurants, but the best things are the buildings that surround them: they embody the city’s history.