In the center of Madrid, an old power plant floats a few meters off of the ground, framed by a vertical garden. On the ground, a mosaic of concrete triangles leads inside to stairways of impossible perspectives housing a piece of global culture.

The Caixa Forum headquarters in Madrid was designed by architects Jaques Herzog and Pierre De Meuron and built by Ferrovial. It hearkens back to a world fueled by coal and looks to the future with knowledge as its guide.

Construction consisted of transforming the old Central Eléctrica del Mediodía, a 19th-century building designed to supply energy to southern Madrid in bygone times. Today, the exterior of the Caixa Forum building still preserves the look of a factory that has been abandoned for years. It has, however, grown from the original 2,000 square meters to some 10,000.

The only thing not preserved from the original structure was a large granite plinth. After it was removed, the new building appears to float over the plaza. Those 2,500 square meters connect the space with the Prado Museum, a hub of cultural activity.

Its architecture plays with the environment, too. The square where the building is located is decorated with a vertical garden standing 24 meters high. Patrick Blanc’s work consists of 15,000 plants from 25 different species. They survive without soil – only water and nutrients.

Inside is where the engineering becomes truly remarkable. The central staircase widens as it climbs. The main floor can be accessed by a metal staircase that loops in a spiral. The other floors open up around another circular staircase. The building’s seven levels (two of which are underground) house exhibition halls, an auditorium, conservation workshops, and other commercial spaces.