|Madrid became the Spanish capital in 1561, when Felipe II moved the Imperial Court to Madrid, although without making any official declaration. The population of Madrid was at this time around 25,000. Only for a brief period between 1601 and 1606, when Felipe III installed his court in Valladolid, has Madrid not been the capital since 1561.
The popular center of Madrid is the famous square, the Puerta del Sol, in the main shopping district and hub of the city's nightlife. Madrid's most accessible green space is Retiro Park. A former royal retreat, its attractions include boating and summer concerts. The Botanical Gardens, a short walk from the Prado, are also worth a visit.
Madrid has three superb art museums. The Prado has one of the most remarkable art collections in the world, with works by major Spanish and European masters from the Renaissance onwards. The Museo Nacional Centro de Arte Reina Sofia is devoted to 20th-century Spanish art with representative works by Miró, Dalí, Juan Gris, and above all by the Cubists, including Picasso. The most famous work on show is his masterpiece from the Civil War period, Guernica. The Museo Thyssen-Bornemisza is one of the most important private collections of western painting in the world, with more than 800 paintings from the Italian Renaissance to the 20-century avant garde.
The Royal Palace dates from the mid-18th century. There are more than 20 rooms open to the public, exhibiting priceless tapestries, paintings, carpets, clocks, furniture silverware and porcelain. The armory has one of the most valuable collections in Europe, mainly from the 16th century. Madrid's most historic square, the Plaza Mayor, is enclosed by arcades sheltering a variety of craft shops, restaurants and tapas bars. It was completed in 1617 during the reign of Philip III.