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. During the middle ages the site was just a market place outside the city walls, however, the construction of the new Plaza Mayor turned the site into a real, large square, measuring 120 meters long and 90 meters wide (394ft. x 295ft). It was surrounded by wooden buildings, at one point up to six stories high. Fires have destroyed all buildings around Plaza Mayor three times in history; in 1631, 1672 and 1790. Each time they were rebuild, the last reconstruction after the fire in 1790, is what we see today.
Among the most visited tourist attractions in Madrid are: El Rastro, an enormous outdoor market. There are market stalls stocking excellent value items, and you can buy almost anything. It gets very busy, so you have to be prepared to go with the slow moving flow of people, but is is full of color and makes for an interesting mornings shopping.
The Prado is one of the worlds most famous art museums, containing masterpieces from the 12th to the 19th century. There are both temporary and permanent exhibitions, and the works of Goya, Rubens and Murillo are amongst the masterpieces on display. The museum is large, and art lovers will easily pass half, if not the whole day inside.
The Reina Sofia art museum makes up part as another of Madrid's selection of famous museums. It houses an extremely important collection of 20th and 21st century art. Picasso's famous Guernica is well worth a look, as are the works of Miro and Dali.
Retiro Park is a wonderful oasis to the east of the center of Madrid. The park was once a palace garden, and it contains a boating lake and many majestic fountains.
The Palacio Real is an enormous and imposing building constructed during the 18th and 19th century. It is the official residence of the Spanish Royal Family, although they only use it for state occasions. It's sheer scale and vast courtyard is impressive, and you can enter the palace to get a look at the lavish halls, the banqueting rooms, throne room, residential areas, the Royal Armory and the Royal Pharmacy.