Since the construction of Mies van der Rohe's Barcelona Pavilion for the World Exhibition in 1929, Barcelona has been at the vanguard of modern architecture. The building by Mies van der Rohe is one of the first so called modern buildings in Europe. It came out of the Bauhaus school and brought with it a whole new way of thinking architecture. The change in style is especially significant in Barcelona. Until the 1920's, Barcelona had been completely dominated by Art Nouveau (called modernisme in Catalan). With funcionalism came a style that was at the same time classic and modern, but first of all was radically opposed to the baroque and ornamented style of Art Nouveau.
However, even though early functionalism is closely linked with Barcelona, it it is not until recent years that vanguardist modernism "came back to" Barcelona. Of course there are exceptions (one significant one is the Fundació Miró by Josep Lluis Sert, a Catalan architect that worked with Le Corbusier in Paris around 1930).
Since then, new interesting, modern architecture has continued to come up in Barcelona. Today Barcelona offers an overwhelming amount of fascinating, modern buildings that have changed the urban landscape of Barcelona radically. To name just a few: Norman Foster, Santiago Calatrava, Jean Nouvel, Richard Rogers, Zaha Hadid as well as local architects like Enric Miralles and Ricard Bofill have been building in Barcelona over the last two decades.
Enric Miralles' Gas Natural building (click the photo to see it in higher resolution)
To help you choose a few of the most interesting of Barcelonas modern buildings, here is a list of some of the best works.
Hotel W has several interesting restaurants and bars, among these the eclipse bar on the 26th floor, and the Restaurant Bravo on the first run by local gourmet chef Carles Abellan (read more about Barcelonas best restaurants). The building rises towards the sky from the marina in the southern part of Barceloneta. The building has been critized for being too close to the sea by environmental associations, but it is also acclaimed for being one of the most interesting works of architecture in Barcelona over the last years.
The architect Ricard Bofill, is also the designer of the Terminal 1 and 2 in the Airport of Barcelona and The National Theater (Teatre Nacional de Catalunya). Abroad he has among other things built the wine cellars of the acclaimed Château Lafite Rothschild.
The communications tower is a both unique an aesthetically close-to-perfection structure on the Montjuïc Hill in Barcelona that looks like a white dart beeing thrown at the sky. It can be seen from most points in Barcelona and is today one of the main architectonical attractions of the city. Early drawings and sketches from Calatrava's hand show that the inspiration comes from a kneeling woman.
The base of the antenna can be seen as a tribute to local architect Antoni Gaudí. It consists of a mosaic of broken tiles in the style of Gaudi's trencadís found in so many of his works: (the rooftops of Palau Güell, Casa Batlló and Casa Milà and also in the famous, meandering bench in Park Güel)l. The Communication Tower changes perspective from different angles, so when you visit it, be sure to walk around it.
The idea of the complex structure of the roof comes from the school designed for Sagrada Familia by Antoni Gaudí. The structure has the form of a hyperbolic paraboloid, one of the favorite geometrical forms of Gaudí.
The museum is a characteristical white building, typical of Meiers other works (for example the Ghetty Museum in Los Angeles). The building is also used for other purposes than exposing art, here among the electronic music festival Sonar.
Here are five more buildings that may be of interest during your stay in Barcelona.
Communications Tower by Santiago Calatrava (click the photo to see it in higher resolution))The Diagonal Mar (also called the Forum Area) is the area in Barcelona with some of the most interesting modern architecture to be visited. The area is ideal if you are short on time and do not have a car to get around.
You can start with the main building in the area, the Forum Building (see above) by the Swiz architects Herzog & de Meuron. Close by, you will find Josep Lluís Mateo's Centre de Convencions Internacional de Barcelona (CCIB) and the Diagonal ZeroZero Tower by Enric Massip Bosch (see above). In a few years you will also be able to visit Zaha Hadid's Torre Espiral, but it is still uncertain when it will be finished.
Closer to the sea you will see a beautiful structures arise, the Photovoltaic Power Plant by Martinez Lapeña - Torres Arquitectos, providing electricity to more than 1000 houses in the area Diagonal Mar Area. If you continue up the Diagonal Street (in the direction of the city center) and you will see the funny looking Diagonal Mar Park designed by Enric Miralles on your left hand. If you continue along the Diagonal street you will get to another parc, designed by Jean Nouvel. Not many people visit this but it is still worth a visit.
A little further up the Diagonal street you will come to Hotel Me by Dominique Perrault, a design hotel with lounge music and trendy restaurants. At the top you can visit the Dos Cielos restaurant (1 Michelin Star). Since now you are getting to Glories, you can easily reach Jean Nouvel's Torre Agbar (see above) and the brand new Barcelona Disseny Hub by MBM (Martorell, Bohigas & Mackey), both located at the Glories roundabout.

L'Auditori by Rafael Moneo in Barcelona (click the photo to see it in higher resolution)
Read about the Barcelona modern Architecture Tour
Read more about the Comprehensive City Tour