I totally recommend staying at Mercedes’ place. It’s so well located with a 5 minute walk from Atocha station. The furniture and decor is upbeat and quirky, absolutely loved it! She is also a very smart knowledgeable woman and we had nice chats over tea. The room has a single bed and a small table and the biggest plus is the balcony which overlooks trees and a church, which feels very peaceful after the end of a long day sight-seeing.