A fabulous promenade leading from the port to Placa de Catalunya, the center of old Barcelona, La Rambla is lined with shops, cafes, flower stalls, street performers and a wonderful food market called Boqueria. You'll pass by the Gran Teatre del Liceu, Barcelona's circa-1847 opera house (it was gutted by a fire in 1994 but has been rebuilt). La Rambla ends at the Placa de Catalunya -- a huge plaza that is the heart of the city and is surrounded by shops and cafes.
La Sagrada Familia, Barcelona's funkiest church, was designed by Gaudi. The most unusual thing about it? It's not finished yet! He began working on it in 1883 and designed intriguing features such as the bell towers, covered in Venetian mosaics, and the nativity-themed facade, with doorways representing faith, hope and charity. Services are held in the crypt where Gaudi is buried. The best way to experience Sagrada Familia is to take the elevator to the top of one of the towers; there's an awesome view from that height. Also be sure to spend some time in the church museum. The Nativity Facade and Crypt of the Sagrada Familia are, along with six other of the city's Gaudi works, a UNESCO World Heritage Site. The church is scheduled to be finished in 2026.
The Museum of Contemporary Art (MACBA) is Barcelona's ode to the art of the past few decades, housing works by major international figures (Klee, Broodthaers) as well as the biggest up-and-coming Catalonian artists.
Architect Antoni Gaudi designed Palau Guell, a gorgeous late-19th-century palace capped with whimsical, brightly colored chimneys. It's part of the Works of Antoni Gaudi UNESCO World Heritage Site.
Another Gaudi design, Parc Guell is a pleasant public park overlooking the city -- a maze of tropical flowers and colorful accents. The entrance is guarded by a mosaic lizard and two fanciful gatehouses (one of which houses a souvenir shop).
Gaudi's brilliant colors and fantastical designs can be seen at two other must-visit sites: Casa Batllo (known by the locals as Casa dels Ossos, or "house of bones") and Casa Mila (commonly known as La Pedrera, or "the quarry"), both located on Passeig de Gracia.
For a look at Barcelona at its most gracious, pay a visit to the Eixample neighborhood north of Placa de Catalunya; in addition to some of the Gaudi sites mentioned above, this is also the home of the city's toniest boutiques, galleries, antique shops and restaurants. This "extension" to the city is home to an abundance of architecture from the turn of the 20th century.
Visit the atmospheric Barri Gotic, Barcelona's Gothic quarter, where the architecture dates back to the 13th century. Streets are winding and narrow, and there are numerous boutiques and antique and artisan galleries. One of its best-known attractions is the Picasso Museum; founded in 1963, the museum specializes in the works of Pablo Picasso (he donated works himself). Also in the neighborhood is the Barcelona Cathedral, parts of which date back to 1298. Santa Maria del Mar is another church worth inspecting; it is, for this ornate city, unusually simple and quite elegant. It was built between 1329 and 1383.
Sports enthusiasts will enjoy a trip to Olympic Stadium. It existed before the Olympic Games were held there, but it was completely remodeled in 1992 just for the occasion. These days, the stadium is used for various events.
The village of Montjuic rises 700 feet above the city's commercial port and is chock-a-block with cafes, boutiques, art galleries and museums. Not to be missed is the Archaeological Museum of Catalonia, which showcases artifacts from the region's prehistoric cultures. Another highlight is the Fundacio Joan Miro, which features tapestries, paintings and sculptures by the Catalonian Surrealist. Another key art museum in this area is the Museu Nacional d'Art de Catalunya; it's got one of the world's premier collections of Romanesque art.
One fun attraction right in town is the Museu de L'Erotica, located on La Rambla. More than a tawdry peep show, the museum (the only one of its kind in Spain) showcases sexuality through the ages and contains a variety of artifacts from all over the world -- everything from Buddhist sculptures to modern-day photography and art.
Take a pilgrimage to Montserrat. The "Serrated Mountain" -- more than 4,000 feet high -- is an exquisite setting for a monastery. The original church opened in 1592, though Montserrat is an ongoing work in progress. While the complex includes shops and cafes, the real points of interest are the Basilica Facade and the Black Virgin -- the soul of the monastery. Other features include the Placa de Santa Maria with its Gothic cloisters and the museum, which exhibits works of art from Catalonia along with Mesopotamia. If you're visiting in the early afternoon (around 1 p.m.) try to catch the male choir singing Virolai, the hymn of Montserrat. Montserrat is a working monastery and is home to Benedictine monks. It's easy to get there; a train runs regularly from Barcelona's Placa Espanya; the journey takes about an hour.
For serious beach time, your best bet is to take a RENFE train to the coastal town of Sant Pol de Mar, about a 60-minute ride away.