It has been recognised as one of the most important buildings of the city of Madrid. The Tower of Banco de Bilbao sits in the madrilenean avenue Paseo de la Castellana, from which it overlooks the city centre through a corner that never achieves to be one. Its curved vertex hides behind it high precision and technique, as much as needed for an engine or any machine straight out of the engineering world. Now, 36 years after its opening, the BBVA Tower shows its recently renovated innards and gives us a masterclass about accessibility, environmental sustainability and technology. A look to the future from inside a milestone of 20th-century Spanish architecture.