The collection of the Prado began as part of the Spanish Royal Collection. King Charles III commissioned the construction of the current building in 1785 as part of an urban renewal project that was to revitalize the city. The building was completed years later during the reign of Fernando VII, grandson of Charles III. Construction took many years and was interrupted by the War of Independence. Eventually in 1819, the building that was to house the present day Prado was finished. The Spanish Royal Collection had a new home. Upon the death of Fernando VII, the inheritance of the collection to his heirs became a major issue when Fernando VII willed half of the collection to each of his daughters -- Isabella II and her sister Luisa Fernanda. Eventually, the dispute was settled when Isabella was deposed and the art collection was nationalized. During the Spanish Civil War, the collections of the Prado were heroically moved by brave citizens from Madrid to Geneva, Switzerland and returned during World War II when the Prado was reopened.
The Prado is the largest art museum in the world and houses more than 9,000 works. Due to space constraints, as much as 80% of the collection remains undisplayed and in storage. In order to show off these works, the Prado rotates displays and collections from time to time. The Prado, one of Madrid's top tourist attractions, attracts more than 2 million patrons a year.