El Escorial Crypt

Source: http://elzo-meridianos.blogspot.com.es/2010/04/el-lugar-donde-acaban-los-reyes-el.html

One of the most curious spaces of the Royal Monastery of El Escorial is the royal crypt, where many of the former monarchs of the Hispanic Monarchy and Spain are buried. As we studied, the monastery was built by Philip II, who conceived it as his residence ans also as resting place for him and the members of his family. That's why he ordered the construction of a crypt or pantheon beneath the church.

A. Altar of the Basilica

B. Burial place 

C. Crypt (Panteón de Reyes, s. XVII)

D. Choir of the Chapel (Panteón de Infantes, s. XVII)

E.  Choir for the monks

F. Tabernacle

G. Philip II's summer room

Source: http://es.wikipedia.org/wiki/Cripta_Real_del_Monasterio_de_El_Escorial

The crypt contains 26 marble sepulchers plus two additional ones over the entrance and it's reserved for the ruling monarchs and  and their spouses. The monarchs' tombs are on one side and their spouses are on the opposite side. Isabella II is the only queen on the monarchs' side and Francisco de Asís' tomb, her husband, is located on the spouses' side. On the following drawing you can observe the distribution of the tombs: (the monarchs on the left and their spouses on the right): 

  

Source: http://www.unofficialroyalty.com/royal-burial-sites/spanish-royal-burial-sites/spanish-royal-burial-sites-of-the-kingdom-of-spain-1516-present/

The first monarchs to be buried there were Philip II's parents, Charles V and Isabella of Portugal. The ruling monarchs who are not buried in the crypt are the following: 

- Philip V, buried at La Granja Palace, in Segovia

- Ferdinand VI, buried at the Royal Monastery of Las Salesas Reales, in Madrid. As his wife Bárbara of Braganza didn't have children, she didn't have the right to be buried in El Escorial (the spouses only have the right to rest there if they were mothers/fathers of kings) and she was buried in Madrid. Ferdinand VI decided to rest with her

- Joseph I and  Amadeus I, foreign monarchs who didn't finish their reign in Spain

The last monarchs to be buried in the crypt were Alphonse XIII and his wife Victoria Eugenia. There are two tombs reserved for Juan of Borbón and his wife Mª de las Mercedes, King Juan Carlos I's parents. They didn't reign, but as they were the king's parents, they are going to be buried on the right side. 

There is a rotting room (el "pudridero"), where the corpses of the dead remain for some years until they can be placed inside the funerary urns. At the moment, the King's parents are in this rotting room. This is the only existing picture of the rotting room:

Source: http://elzo-meridianos.blogspot.com.es/2010/04/el-lugar-donde-acaban-los-reyes-el.html

Other members of the royal family (infantes, infantas and the queens who were not mothers of a king) are buried in the Pantheon of Infantes, which includes several rooms that host around 100 corpses. There is a curious tomb, with the shape of a birthday cake, reserved for the infants who died before having received the first communion. Here you have it: 

Source: http://www.travelinginspain.com/el_escorial_Crypt.html

If you want to read more about El Escorial Royal Pantheon, here you have two more links: 

http://www.unofficialroyalty.com/royal-burial-sites/spanish-royal-burial-sites/spanish-royal-burial-sites-of-the-kingdom-of-spain-1516-present/

http://www.travelinginspain.com/el_escorial_Crypt.html