The firm Ruiz-Larrea & Asociados has been commissioned to renovate Cibeles Tower, an office block located in the courtyard of the Bank of Spain’s head offices, on Madrid’s Calle Alcalá. The intervention seeks to adapt the building to the surroundings and to the needs of the program, and plays out on three levels: infrastructural, functional, and energy-related. New circulation systems are provided, both for users and for technical installations. This reorganization makes it possible to optimize uses, giving rise to a free plan that can be modularized with dry-installed elements. Finally, the building is given a new skin, making it more energy-efficient.