One of the first 21st-century hotels to be shoehorned into an old building near Puerta del Sol, the Ateneo set the standard for a modest boutique lodging with its marble and stainless baths with combination tub-showers, its double-glazed windows to keep out the racket of Sol, and its comfortable, large beds in bigger than usual rooms. (During busy times they’ll sometimes pass off a small room with a double bed that’s otherwise rented as a single; ask for another.) Furniture tends to be comfortably upholstered, and most rooms have a spacious desk and a good desk chair. Family rooms can accommodate two adults and one or two children.