The Museo del Prado, together with Museo Thyssen-Bornemisza and Reina Sofía, forms one point of the renowned "golden triangle of the arts". El Prado is one of the world's foremost art museums, a result of the collection mania of the Spanish monarchy and its once wide empire, and it holds works by the most outstanding Spanish and foreign artists from all periods between the XII and the XIX century. It can be viewed as a living encyclopaedia of world art, of the history of art. Its Flemish collection, Titian, Rubens and the bizarre paintings of Hieronymus Bosch will keep you entertained for quite a while. We know that by the XV century, Spain's Queen Isabel and King Fernando el Católico ("The Catholic Kings of Spain") already had a group of artists employed by the Crown. But the "collection mania" of the Habsburgs started the following century, with Charles V, followed by Philip II, who acquired works by El Bosco, Tintoretto, Tiziano and other famous artists. In 1818 it was decided to show the entire royal art collection to the public, leading to the conversion of the previous “Museum of Natural Sciences”, built by Spanish architect Villanueva, into the current “Museo del Prado”. At present the building is being extended towards the area of Los Jerónimos (architect Rafael Moneo), with the aim of enlarging the exhibition area in the short term (the whole museum’s collection, 3000 thousand paintings, will be shown – instead of the current 1500).