Hostal Ballesta 

The hostel has a great location, just a few meters from a very central avenue, Gran Via, from where you can explore on foot or by taking public transportation, which has very good service, or by taking the metro with two stations very close by (Gran Via and Callao). The frequent taxi service is another option. It's also nearby a variety of restaurants and food stalls. There are many shopping centres for those who prefer to shop. It's very safe for solo travellers. The 24-hour staff offers security and is very attentive to provide information if you need it. The rooms and hallways are always kept clean. The room service is impeccable. Regarding the surroundings, the only unpleasant experience is the women "street workers," who are often a bit noisy. I was very satisfied with my stay.