The Basílica takes the form of a Greek cross and its central cupola is crowned by a dome 92 metres high, which makes it stand out among the other towers of the building. The majority of its frescos above the vaults were painted by Lucas Jordan in the 17th century, except those located above the Choir and the main altar which are the work of Luca Cambiasso. The main altar is decorated with paintings by Zucaro and Tibaldi. At either side of the main altar there are bronze depictions of Carlos V and Felipe II with their respective families by Pompeyo and León Leoni.
The library, Biblioteca, has one of the most valuable collections in the world, not due to the quantity of documents and books, as there are around 50,000 volumes, but due to the quality of these, the collections of Arabic, Hebrew and Latin manuscripts being especially precious. The room, open to the public, is a vaulted gallery measuring 54 metres long by 9 metres wide. It is decorated with paintings by Tibaldi and Carducci, from the 16th century. The iconographic programme is very interesting: to the north, Philosophy is represented; opposite it is Theology; and between the two are the seven Liberal Arts – Grammar, Rhetoric, Dialectic, Arithmetic, Music, Geometry and Astronomy.
The crypt called the Pantheon of the Kings, Panteón de Reyes, is located under the main altar, and here are buried practically all the kings of Spain from Carlos I onwards, except for Felipe V, Fernando VI and Amadeo de Saboya. The Pantheon is an octagonal room. On one of its sides is the entrance and on the opposite side is an altar with a gilded bronze figure of Christ by Domenico Guido. The room is decorated with deep-red and grey marbles and gilded bronze.
The crypt for the Princes and Princesses, Panteón de Infantes, was created in the middle of the 19th century, during the reign of Isabel II, and the works were completed in 1886. Constructed of white marble, it is made up of nine rooms. In the first is a bronze sculpture of Isabel II praying. The most notable tomb of this pantheon is that of Juan de Austria, illegitimate son of Carlos V. In another of the rooms, there is a great collective tomb in the shape of a cake in which are buried some of the children of the royal families who died before their First Communion.
The palaces, Palacios, occupy part of the north facade and that of the east, in addition to the projecting wall of the basilica. The palace rooms from the 16th century were occupied by Felipe II. The first of these is known as the Hall of Battles, Sala de las Batallas, decorated with paintings by Genoese artists: Oracio Cambiaso, Fabricio Castello, Nicolas Granello and Lazaro Tavarone. These painted battle scenes, among which were the battle of la Higueruela and the battle of St. Quentin. In another of the rooms, you can see the sedan chair which carried Felipe II at the end of his life, when, due to the gout, he was barely able to walk. The Portrait Room, the Map Room and the Throne Room take us through to the bedroom where the King died, characterised by simplicity. The Bourbon Palace, Palacio de los Borbones, was decorated at the end of the 18th century, under Carlos III and his son, Carlos IV. The influence of French taste is apparent in the style of the furniture, porcelain, lamps and all manner of decorative objects. The most important items in these rooms are the collection of tapestries designed by artists such as Goya, Bayeu and Tenniers, among others.
The Chapter Rooms, Salas Capitulares, as their name indicates, were used by the monks to celebrate their chapter meetings. The ceilings were decorated in Pompey style and although a large part of their artistic richness went to the New Museums, they still contain works by El Greco, Rivera, Tintoreto, Titian and El Bosco.
The new museums, Nuevos Museos, are divided into two themes: painting and architecture. In the art museum, Pinacoteca, we can find works by Titian, José de Rivera, Lucas Jordan, Bassano and El Greco, among others.
The architectural museum, Museo de Arquitectura, houses an important collection of tools, models, plans and mechanisms used during the construction of the Monastery.
Outside, the Garden of the Friars, El Jardín de los Frailes, and the Gallery of Convalescents, Galería de convalecientes, stand out. Felipe II was a great nature lover and so the Jardín de los Frailes is an ample garden, containing a dozen green parterres around an equal number of small ponds, each with a water fountain at their centre. These gardens, in the most northern end, are crowned by one of the more beautiful architectural features, the Galería de Convalecientes, located between the Infirmary and the Pharmacy Tower, which is placed upon a set of Doric columns forming a right angle.
The Monastery of San Lorenzo de El Escorial was declared a Historic-Artistic Monument in 1931, and in 1984 was recognised by UNESCO as a World Heritage Site.