You should not leave Madrid without visiting this impressive monument built between 1563 and 1584, with an area of 33,327 m², National Patrimony and UNESCO Heritage since 1984.
If your budget is small or you do not have enough to see all the museums and historical monuments you want, you can consult this guide of the Hotel Miau so you can plan the visits that will not cost you anything ... and if you go early you can be the first in the row, avoiding long queues.