The architecture is part of what's made Barcelona one of the design capitals of the world and a mecca for architects and students of major architectural influences.

Barcelona is most famous for the architecture of Antoni Gaudi. Gaudi had a unique and highly unusual style which make his buildings look fanciful and inspirational. He built during a time of great prosperity in the city, at the turn of the 19th-20th century, when manufacturing brought new technologies when the art of the craftsman was still an integral part of the process. Gaudi's buildings, inspired by a combination of nature and Catalan and Christian symbolism, have been compared to human bones, animals and plants. Some almost look as though they are made of melting ice cream! 

The most famous Gaudi building is probably the Sagrada Familia Cathedral, which began construction in 1882, and is still under construction today.  This enormous landmark church remains covered with scaffolding as work still continues on it in accordance with Gaudi's original plans from over 100 years ago.  It is a wild, Gothic creation with 20 spiraling towers representing major Christian figures such as the Apostles, and is a must see on a trip to Barcelona.  Only one elaborately constructed facade (the Nativity) was completed in Gaudi's lifetime; the contrastingly stark Passion facade was completed later, with haunting sculptures by Subirachs. Initial work is just beginning on the Glory facade . A good overview of the city can be seen from Montjuic (Jewish Hill) which has a sky tram to take you to the top.  You can view the Mediterranean Sea and the fabulous churches from this vantage point.

But Sagrada Familia isn't Gaudi's only masterpiece. La Pedrera (also known as Casa Mila) is well-known for its famous facade that has no corners at all. "La Pedrera" is the name the people gave the building, which literally translates as "the quarry." It's pretty cool for a building conceived in the early 20th century, which was also considered radical and unacceptable at the time. Casa Battlo, a few blocks down the Passeig de Gracia from La Pedrera, is another Gaudi masterpiece, though he designed its renovation, using an existing structure. The careful planning that went into the engineering of Casa Battlo, from ventilation to decoration, is astounding. The block in which Gaudi's Casa Battlo sits was known as "La Manzana de Discordia" (the block of discord), for the disparate styles represented by the homes created for some of the city's wealthiest families around 1900.

The Palacio Guell, off La Rambla, was an earlier building created by Gaudi for the man who became a lifelong benefactor and champion of the architect's work, the wealthy industrialist Eusebi Güell. There is also the Güell Park, made for Gaudi's wealthy "sponsor". This was originally intended to be a self-enclosed housing community away from the city, but only three homes were even built (one of which Gaudi lived in for a time with his father and niece). The site was eventually given to the city, which made it the famous public park it is today. You should check out the huge bench that goes all around the main elevated square which has city views. Gaudi made one of the workers sit on the bench, to make a print, so the bench would anatomically fit to the human body. He constructed everything without using any cement. The buildings had been standing there for years, until modern architects decided to apply some cement to "glue" it.The comprehensive estate design included stately gardens, entrance buildings, water catchment features and a reservoir, all lavishly embellished with his trademark intricate ceramic tiling detail.

While a little way outside the city, Gaudi's crypt for Colonia Güell is also worth a visit. It was intended to be a much larger building for Güell's industrial town, which Gaudi created at a slower pace than any of his other buildings. However, its strange logic and rustic appearance combined with intricate design elements makes it one of his great works. It's also on this building that Gaudi conducted many of his architectural experiments, which he later applied to the Sagrada Familia.

Gaudi died unexpectedly while buiding his masterpiece, Sagrada Familia Cathedral, after he was hit by a tram when allegedly standing back to view the building from the road. The irony was that he hated modern technology of the time; he insisted, for instance, that public transportation went nowhere near Park Güell. He was struck while crossing the street and subsequently died alone in a mediocre hospital, unrecognized until hours/days later, despite his popularity. No one recognized him at first because he had long before renounced fame and fortune, living at Sagrada Familia like a penitent monk and dressing in rumpled old clothes.

But Barcelona is even more than "Gaudi". His pupils and contemporaries like Puig i Cadafalch or  Domenech i Montaner were also very important architects, leaving amazing buildings to the city like the " Palau de la Musica Catalana" and the " Hospital de Sant Pau" (both of which still operate as the performance hall and hospital for which they were originally built), as well as many other interesting buildings around the city.

Barcelona is full of "modernista" (art nouveau) buildings created in the late 19th and early 20th century. The city never ceased its interest in new creations, from the 80's "Edifici Trade" of Antoni Coderch to the new Montjuic communications tower to the Sant Marti bridge designed by Santiago Calatrava. International architects also love Barcelona. Isozaky and Foster left their mark, as has Frank Gehry.  More recent buildings coninue in the Barcelona tradition of landmark design and architecture.