It took 5 years to transform this former power station on Paseo del Prado into a dynamo for contemporary art. The Pritzker Prize-winning architectural firm Herzog de Meuron managed to multiply the floor space fivefold while creating a brick structure that seems to levitate above the plaza. One of its many eye-catching features is the 24-meter-high (79-ft.) Jardin Vertical—a living wall covered with 250 species of plants. The interior of the building is equally striking. Although La Caixa has permanent collections, it is best known for its constantly changing exhibitions of contemporary art and photography. There are usually three major exhibitions on display at a given time. Many are accompanied by lectures, concerts, and panel discussions.