When you have a free day during your internship, you have the possibility to visit Barcelona. Maybe this internship is your first experience abroad, or beside for your internship you’ve never had been in Spain before or you just have never been in Barcelona. Here are some pieces of advice if you go to Barcelona when you have a free day. Take the train to the station called Barcelona Plaça Catalunya. From there you walk to Passeig de Gràcia. Once you have seen the Passeig de Gracia, you need to take the metro (L1, L2, L4, L5) to Plaça Urquinaona. From here you walk to the Casa Calvet. Once you have seen Casa Velvet, you must go by metro (L2, L3, L4) to the stop called Passeig de Gràcia. Here you will visit Casa Batllò. After you have seen Casa Batllò you continue the tour by taking the metro (L3) till the stop called Diagonal. Here you will visit Casa Milà ´La Padrera´.   

Take the train to the station called Barcelona Plaça Catalunya. From there you walk to Passeig de Gràcia. After you have seen the Passeig de Gracia, you need to take the metro (L1, L2, L4, L5) to Plaça Urquinaona. From here you walk to the Casa Calvet. After you have seen Casa Velvet, you must go by metro (L2, L3, L4) to the stop called Passeig de Gràcia. Here you will visit Casa Batllò. After you have seen Casa Batllò you continue the tour by taking the metro (L3) till the stop called Diagonal. Here you will visit Casa Milà ´La Padrera´.

Casa Calvet is a building, designed by Antoni Gaudí for a textile manufacturer which served as both a commercial property (in the basement and on the ground floor) and a residence.

Gaudí scholars agree that this building is the most conventional of his works, partly because it had to be squeezed into older structures and partly because it was sited in one of the most elegant sections of Barcelona. Its symmetry, balance and orderly rhythm are unusual for Gaudí's works. However, the curves and double gable at the top, the projecting oriel at the entrance almost baroque in its drama, and isolated witty details are modernista elements.
Bulging balconies alternate with smaller, shallower balconies. Mushrooms above the oriel at the center allude to the owner's favorite hobby.

Columns flanking the entrance are in the form of stacked bobbins, an allusion to the family business of textile manufacture. Lluís Permanyer claims that "the gallery at ground level is the facade's most outstanding feature, a daring combination of wrought iron and stone in which decorative historical elements such as a cypress, an olive tree, horns of plenty, and the Catalan coat of arms can be discerned".

Three sculpted heads at the top also allude to the owner: One is Sant Pere Màrtir Calvet i Carbonell (the owner's father) and two are saint patrons of Vilassar, Andreu Calvet's home town.

Casa Batlló is a building restored by Antoni Gaudí and Josep Maria Jujol, built in 1877 and remodelled in the years 1905–1907, part of the Illa de la Discòrdia.

The local name for the building is Casa dels ossos (House of Bones), and indeed it does have a visceral, skeletal organic quality. It was originally designed for a middle-class family and situated in a prosperous district of Barcelona.

The building looks very remarkable, like everything Gaudí designed, only identifiable as Modernism or New Art in the broadest sense. The ground floor, in particular, is rather astonishing with tracery, irregular oval windows and flowing sculpted stone work.

It seems that the goal of the designer was to avoid straight lines completely.
Much is decorated with a mosaic made of broken ceramic tiles starts in shades of golden orange moving into greenish blues. The roof is arched and was linked to the back of a dragon or dinosaur. A common theory about the building is that the rounded feature to the left of centre, terminating at the top in a turret and cross, represents the sword of Saint George, which has been plunged into the back of the dragon.

Casa Milà, better known as La Pedrera, is a building designed by Antoni Gaudí, and built during the years 1906–1910, being considered officially completed in 1912.

 It was built for a married couple, Rosario Segimon and Pere Milà. Rosario Segimon was the wealthy widow of José Guardiola, an Indiano, a term applied locally to the Catalans returning from the American colonies with tremendous wealth. Her second husband, Pere Milà, was a developer who was criticized for his flamboyant lifestyle and ridiculed by the contemporary residents of Barcelona, when they joked about his love of money and opulence, wondering if he was not rather more interested in "the widow’s guardiola", than in "Guardiola’s widow".

The design by Gaudi was not followed in some aspects. The local government objected to some aspects of the project, fined the owners for many infractions of building codes, ordered the demolition of aspects exceeding the height standard for the city, and refused to approve the installation of a huge sculpture at the top of the building, described as "the Virgin".
Casa Milà was in poor conditions in the early 1980s. It had been painted a dreary brown and many of its interior color schemes had been abandoned or allowed to deteriorate, but it has been restored and many of the original colors revived.