Spain - Barcelona - Torre Agbar - sq
From Wikipedia : "Its design combines a number of different architectural concepts, resulting in a striking structure built with reinforced concrete, covered with a facade of glass, and over 4,500 window openings cut out of the structural concrete. The building stands out in Barcelona; it is the third tallest building in Barcelona, only after the Arts Hotel and the Mapfre Tower, both 154 m (505.25 ft).
A defining feature of the building is its nocturnal illumination. It has 4,500 LED luminous devices that allow generation of luminous images in the façade. In addition, it has temperature sensors in the outside of the tower that regulate the opening and closing of the window blinds of the façade of the building, 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."