The Agbar Tower is an imposing skyscraper in Barcelona marking the entrance to the most modern part of the city. The ultra-modern structure is 144 metres tall and features 38 floors; at the time of its opening in June 2005, it was the third tallest building in Catalonia. Designed by the French architect Jean Nouvel, the building is an expression of the union of two opposing concepts: lightness of glass that covers the building and the massiveness of the concrete undergirding its structure. As the architect himself once remarked, the characteristic shape of the tower was inspired by the mountain range of Montserrat just outside of Barcelona and the image of hot springs spraying water into the air.

The design of Agbar Tower is a brave combination of a number of different architectural concepts, resulting in an original construction of reinforced concrete with a glass facade dotted with nearly 5,000 windows. The building has almost 51,000 square metres of floor space, of which over 30,000 contains offices. One very characteristic feature of the tower is its breathtaking nighttime illumination.Over 4,500 luminous LED points generate lighted images all over the building's facade, displaying a staggering range of 16 million colours and allowing for effective independent image transitions.