In the north of Madrid, in the Tetuán district, the new headquarters of Metro Madrid is being built. This building complex consists of a total of six buildings. The first two buildings were completed in 2021. They form the heart of the new Metro Madrid headquarters and house the company’s new administrative and technology centre on up to 12 storeys, with state-of-the-art workplaces for around 1,000 people. A second phase of the project will see the construction of the other buildings, which will house other functional areas of Metro Madrid as well as a museum dedicated to transport. The buildings are designed according to the lowest energy house standard. To this end, the buildings have their own energy generation, including photovoltaic panels, geothermal wells, lighting with natural light sensors and LED technology, water harvesting or green roofs. The site on which the new Metro headquarters is being built is the old metro depot at Plaza Castilla. The abandoned-looking site in the middle of Madrid is experiencing a revival with the new buildings of the Metro headquarters and thus, to a certain extent, an upgrading of the entire neighbourhood. The black architectural shell of the buildings consists of a ribbed construction of prefabricated concrete elements that runs vertically along the length of the buildings. To preserve the materiality of the concrete of these ribs unaltered, the concrete elements were coated with KEIM Concretal-Lasur in a black shade.