Opened in 2015, the Principal Madrid is housed in a seven-floor 1917 Spanish Renaissance-style building with Art Nouveau and Art Deco flourishes. The interiors retain the building's high ceilings, iron railings, marble floors, and large windows. The hotel has a discreet front door entrance on a side street off Gran Via. Guests enter and are whisked to the sixth-floor lobby, whose sharp vintage look is best described as New York loft meets British gentleman's club. Leather chesterfield sofas, Indian teak benches, mid-century coffee tables, and handwoven Turkish rugs combine to create an eclectic but sophisticated vibe. Colorful dusty-rose and tangerine-orange curtains offset the muted gray of the lobby and restaurant walls. The local fashion and media crowd mingle with guests and sip inventive cocktails on the large rooftop terrace with olive and cypress trees, tables with covered umbrellas, candies, the sound of flowing water, and a curated music playlist. The terrace offers excellent views of the sunset, Gran Via, and the surrounding cityscape. The Principal draws well-heeled international leisure travelers -- especially couples -- and business travelers for its location and chic ambience.

Centrally located a half-block off Gran Via -- akin to the "Broadway of Madrid" -- the Principal Madrid is near numerous cafes, restaurants, bars, nightclubs, theaters, and high-end shops. The trendy, LGBT-friendly barrio of Chueca is just behind the hotel and is filled with galleries, cafes, bars, and a high-end market. Plaza de Cibeles, with its marble sculptures and fountain, and the vast Retiro Park are about a five-minute walk away. The Principal is well-situated for art lovers -- it's about 10 minutes on foot from the Thyssen-Bornemisza Museum and the Prado, with its Goya and El Greco masterpieces. Puerta del Sol, where locals and tourists gather on New Year's Eve (or any night of the year, really) -- and where three metro lines conveniently converge -- is about a 10-minute walk from the Principal (though the Banco de Espana Metro station is also only two minutes from the hotel on foot). Another hangout for tourists and locals, 17th-century Plaza Mayor, is a 15-minute walk away, and can also be reached by bus or metro. Teatro Real and the Royal Palace are about 10 minutes away by metro, while the Atocha train station and the Reina Sofia art museum, where Picasso's famous "Guernica" occupies an entire room, is about a 20-minute walk or bus ride away. Madrid-Barajas Airport will take 20 minutes to reach by taxi or 40 minutes by metro.

The Principal's 76 tasteful rooms and suites span six floors of this seven-story building. Rooms retain the high ceilings and big windows of the hotel's original building but have a cool and contemporary aesthetic. Walls are various shades of gray, furniture and headboards are black, and the bedding is white -- save for houndstooth-print throws on some beds. A splash of color is provided by the yellow upholstered benches at the end of the beds. Small clusters of stylish black-and-white line drawings hang on the walls. Some rooms have mid-century modern burnt-orange leather butterfly chairs, which provide another pop of color, along with the chrome reading lights. 

Rooms range from 258 square feet (23 square meters) to 538 square feet (50 square meters), so they're spacious by European standards. The plush beds have thick mattresses, feather mattress toppers, Egyptian cotton linens, and come with evening turn-down service. All rooms include desks, safes, free shoeshine service, Nespresso machines with free coffee, and hot water kettles for free tea, though not all rooms have minibars.

The excellent in-room tech includes free Wi-Fi, Bluetooth sound systems with MP3 player and tablet connectivity, and 40-inch flat-screen TVs with more than 40 international channels. Video-game consoles can be rented from the front desk. One suite category features a sitting room, dining room, and two 46-inch flat-screen TVs. Higher-category bookings can also opt for butler service.

The stylish bathrooms are done in a stark black-and-white color palette, and come with magnifying mirrors and premium bath products. All have rainfall showerheads with massage jets, and some have bathtubs. Rooms are all non-smoking. Given the architecture of the building, elevators are a bit small, and can get crowded when several guests with luggage try to get simultaneously get to their rooms. Some rooms have small balconies and views of the Gran Via, though others face the interior courtyard and can be dark.

Given its boutique size and city-center location, there's only so much that can fit into this hotel, but what's on offer is generally outstanding. The acclaimed restaurant, with a Michelin two-star chef, serves innovative Spanish cuisine, with an emphasis on all things local and seasonal. The adjacent bar serves inventive cocktails and appetizers, as does the rooftop terrace bar, which has a deck with lounge chairs, and offers excellent views of the city. The hotel serves a breakfast buffet (for a fee), with items like Iberico ham, tortillas, smoked salmon, cooked-to-order eggs, pancakes, cereal, pastries, and fruit. 

While there is no pool, there is a wellness suite with a wood-paneled sauna, massages and facials available, and a small, limited fitness center, with free weights, one treadmill, two exercise bikes, and plyometric balls. Personal training sessions can also be booked. Access to many wellness features comes at a fee for some guests -- it depends on the category of booking so check ahead.

The hotel has meeting rooms, a business center, concierge service, and baggage assistance. Valet parking is free of charge -- a nice perk given the city center location. Free Wi-Fi is available throughout the property. Those staying in higher-category rooms are entitled to extras based on availability, including outbound airport shuttles, late check-outs, and free sauna access.