The Puerta de Europa towers (Gate of Europe or just Torres KIO) are two twin office buildings in Madrid. They were designed by the American architects Philip Johnson and John Burgee, built by Fomento de Construcciones y Contratas[ and commissioned in 1996 by the Kuwait Investment Office (hence their initial name "Torres KIO" or "KIO Towers"). Leslie E. Robertson Associates, RLLP New York (LERA) provided structural engineering services. Each building is 115 m tall with an inclination of 15°.
They are located near the Chamartin railway station, on the sides of the Plaza Castilla bus station, north from the Paseo de la Castellana and near the Cuatro Torres Business Area.
After the Torres KIO fraud case, KIO had to sell the buildings, which are now owned by Caja Madrid and Realia.