Breaking down sightseeing

One day, start at Gaudi's Park Guell and get ready to climb a hill. Part of the park is free - you can see his viaducts and gardens - but don't skip the paid area. It has a large square lined with a colorful smashed-tile bench and boasts views of the whole city.

Walk back via Carrer Gran de Gracia in the hip Gracia neighborhood, bustling with cafes and shops tucked into modernist buildings. See Gaudi's Casa Vicens, covered with tiles of yellow flowers, down a side street.

Another day, book ahead for a tour of the Basilica de Sagrada Familia, Gaudi's famous unfinished church with breathtaking stained-glass windows. Cranes hoist stones above its towers, working to realize the architect's vision a lifetime later.

Walk 10 minutes to Sant Pau Recinte Modernista, Barcelona's best-kept secret. There are few visitors despite its proximity to the most visited landmark in the city.

It's a UNESCO World Heritage Site along with Montaner's stunning Palau de la Musica Catalana. A paid tour of the music hall's colorful stained glass and mosaics is worth it, and you may even catch musicians practicing.

Montserrat

For a respite from city life, carve out a half-day for this mountain monastery. Load up on snacks and get to Placa d'Espanya train station, where English-speaking workers will help you buy a ticket from the machines for the hourlong train ride.

Take the cable car for 360-degree views of the green valley below and rocky peaks ahead. The church is beautiful, but the mountain was the star. Montserrat boasts lots of walks, including a 5-km jaunt on a paved path from the top of the peak to a viewpoint overlooking the monastery.

Afterward, you could fit in a visit to Casa Mila, which rarely has lines in the evening, and nearby Casa Batllo, with its exterior that resembles crashing waves.