Nice stay at Sergio's place. Natalia met us when we arrived on site, and helped us check in. Very close to Tirso de Molina metro stop, and walkable to majority of Madrid's main sites (puerta del sol, plaza mayor, la latina, barrio de letras). However, extremely loud at night, even for a heavy sleeper like myself. Also it seems as though an old apartment unit has recently be converted into 3-4 other smaller apartments for Airbnb, so it doesn't have much of the original building's charm, and you can hear other guests coming in and out of the main door. Very spacious for two travelers, as there was a separate living room with a kitchenette if you were looking to cook meals while in Madrid. Decorated really nicely, with lots of plants.