it is the third tallest building in the city, after the Arts Hotel and the Mapfre Tower, which both stand tall. A defining feature of the building is its nocturnal illumination. It has 4,500 LED devices that allow generation of luminous images on its façade. In addition, the outside of the tower has temperature sensors that regulate the opening and closing of the window blinds of the façade, reducing the consumption of energy for air conditioning. It houses the head office of the Aigües de Barcelona Group, the water supply company of Barcelona. As explained by Nouvel himself, the construction was strongly influenced by one of the most representative symbols of Catalan culture. One side references the bell towers of the Sagrada Familia by the Catalan architect Antoni Gaudí. (These bell towers were based in turn on the idea of the Hotel Attraction, a course project by the teacher Reus in 1908 for some New York hoteliers, which was redesigned in 1956 by his disciple Joan Matamala. These designs were included in Rem Koolhaas' book Delirious New York, a reference for many architects.) An additional tribute to the Sagrada Família lies in the north side of the tower, which was designed with the intention of obtaining an optimal view of the cathedral. Additionally, Nouvel was inspired by the distinctive pinnacles of the Montserrat mountain range, which are of great significance for the people of Catalonia, as Montserrat houses their patron saint, Our Lady of Montserrat. In designing the Agbar Tower, Nouvel said he rejected the prevailing North American opinion of what a skyscraper should look like. It was the architect's intention to give the impression of land that is emerging out of the ground in a particular fashion. The use of the tower by a water utility company led him to the design of a metaphor of a geyser sprouting from the deep sea. Construction Starting in mid-1999, when activities were initiated for preparing the site, Dragados's, construction project dragged on for nearly six years, finally ending in late 2004. Approximately 1170 workers were engaged in its construction. Features Materials The main materials used in the construction of the building are concrete which comprises the structure of the tower and aluminium and glass in the form of 59,619 strips of painted sheet metal of different colours, covering the approximately 16,000 m2 of exterior surface. In addition, the glass has different