Karmen's apartment has the best location. A 2 minute walk to the Plaza de Espana metro, walking distance to pretty much everything (Sol, Gran Via, Mercado San Miguel, you name it). There is even a very conveniently located cafe just at the corner of Travesia Reloj and Calle de Travesía Fomento. Talk about convenience and easy access. Check-in and check-out are pretty easy and smooth.