The Museu Blau de les Ciencies Naturals, commonly known as the Forum Building was one of the most prominent landmarks present in Barcelona. The structure was designed by two Swiss architects named Pierre de Meuron and Jaques Herzog. The structure and its construction have been the centre of several controversies regarding the fact that there might have been certain structural flaws and defects in the building during its construction. The fact that it cost over $144 million caused it to become a bone of contention because of controversy as well.
The building is situated near the Diagonal Avenue and the Rambla de Prim. It is about 25 meters in height and each side is 180 meters. The edifice has a distinct triangular shape. The Forum features a large auditorium which has the capacity to seat 3200 people. It also has an exhibition hall that spans over 5000 square meters of land, making it one of the most impressive buildings in the city. It is an example of modern architecture in Barcelona, where majority of the buildings have been constructed based on Gothic, Renaissance or Medieval architectural designs. The building was under construction and reached its completion in 2000.

The Bach de Roda in Barcelona is unique in the fact that it was built for a rather unusual purpose. It was mainly constructed for the purpose of moving people and vehicles from one side of the city to the other, but not over roads, rather this was required over railway tracks.
Located in Barcelona, the bridge comprises twin steel arches. These arches have been designed in a way that they look completely unlike any conventional structure that was built for this purpose. It is for this reason that this bridge is able to aid tremendously in moving vehicular traffic as well as people across the railways and it is also quite an interesting sight to behold.
The arches have been designed in a way that each of the arches are completely capable of carrying their particular part of the bridge. Vehicular traffic moves from one side to the other from the centre of the bridge, and this is separated from the pedestrian section which is against the rods. Unlike conventional bridges, this particular one does not have any supporting structures over the road. The mastermind behind the designing of this bridge is Santiago Calatrava, who is famous for designing a number of unique bridges all over the world.

The Torre Agbar, or Agbar Tower, is a 38-story tower located between Diagonal and Carrer Badajoz, near Plaça de les Glòries Catalanes, which marks the gateway to the new technological district of Barcelona, Catalonia, Spain. It was designed by French architect Jean Nouvel in association with the Spanish firm B720 Arquitectos and built by Dragados. The Torre Agbar is located in the Poblenou neighborhood of Barcelona and is named after its owners, the Agbar Group, a holding company whose interests include the Barcelona water company Aigües de Barcelona. The tower has a total of 50,693 square metres, of which 30,000 are in offices, 3,210 in technical facilities, 8,132 in services, including an auditorium, and 9,132 square metres for parking. It opened in June 2005 and was officially opened by the King of Spain on September 16, 2005 and at a cost of 130 million euros.

Located in La Ribera just off the Via Laietana, the Mercat de Santa Caterina was recently remodeled with a colorful undulating roof. During the remodeling, the market was relocated to the stretch of the Passeig de Sant Joan in between the Arc de Triomf and the city's Parc de la Ciutadella. It has been in operation since 1848. It serves an area also previously served by the Mercat del Born, which has been converted into an archaeological site preserving the foundations of the older neighborhood underneath its roof.

The Barcelona Museum of Contemporary Art (Museu d'Art Contemporani de Barcelona, or MACBA) is situated in the Plaça dels Àngels, in El Raval, Ciutat Vella, Barcelona, Spain. It was designed by Richard Meier & Partners (1987-1995). The building’s architectural style has strong references to Modernism. This large (120 by 35 meters) white building has much of its southern elevation glazed, providing the visitor with views across the plaza, and allowing natural light into the interior. It includes a central library, specialized in art books and publications. The museum opened to the public on 28 November 1995. All the art dates from the mid-20th century onward. There are three periods of modern art represented: the first one covers the forties to the sixties; the second spans the sixties and seventies; the third period is contemporary. The collections focus on post-1945 Catalan and Spanish art, although some foreign art is also represented.

The Barcelona Pavilion was built for the occasion of the International Exposition held in Barcelona and during this expo this building was used as the German Pavilion. It is from here that the German portion of the exhibition was displayed and inaugurated. It is a classic example of modern architecture in the city and yet it has great historical value. Materials such as travertine and marble have been used mostly in its construction.
In 1928, Mies was given the charge for the erection of the building with complete artistic management. There was however one condition that he had to follow stringently and that was the time limit of one year that was given to him to complete this project. The economy of the country was also unstable during these times which posed another great challenge to Mies. Once the construction was complete, at the exhibition, the German Pavilion displayed and represented the new Weimar Germany with elements of democracy, prosperity, progression and advanced architecture.
The purpose that the Pavilion was meant to serve at the exhibition was to convey a message to the world, that Germany had marked an era of a new beginning in terms of prosperity and advancements after World War 1.

The Montjuïc Communications tower is an iconic tower that was built in 1991 at the Montjuïc Hill, just southeast of the Barcelona city center. The gracious white beacon is characteristically designed in the style that is known as the architecture of Santiago Calatrava, the Spanish designer of the tower.

Commonly known as the Torre Calatrave or the Torre Terefonica, the Montjuic Tower is the main telecommunication tower of the Catalan city of Barcelona. The construction of this tower initiated in 1989 and the structure reached its completion in 1992. The designer commissioned for this project was Santiago Calatrava.

The tower is situated in the Olympic park and was built for the purpose of transmitting TV signals and coverage of the Olympic games that were held in Barcelona in the summer of 1992. The height of the tower is 136 meters and it is constructed to resemble an athlete with the Olympic Flame in his hand.
Gaudi’s famous mosaic technique known as the Trencadis can be seen at the base of this tower. Because of the history associated with it. It serves not only as a telecommunication tower today but also a memorable structure for those who witnessed its completion before the summer Olympics.