The former royal palace and monastery at El Escorial is another UNESCO site in the Madrid region, located some 30km from the city. In the summer, due to its higher altitude, it makes a nice escape from the heat of Madrid. Dating from the second half of the 16th century, it was built by King Felipe II to commemorate a Spanish battle victory over France. This site is huge and visitors can spend hours wandering around the exquisitely decorated buildings and grounds. The must-sees are the Pantheon (where Spanish monarchs are buried), the Patio of the Kings, Hall of Battles and the Basilica. Art lovers will be thrilled with the many paintings by masters such as Velázquez, Titian and El Greco. Be sure to pause for a few moments to take in the stunning views of the Sierra de Guadarrama mountain range. Allow 2-3 hours to see the buildings and gardens, however note that once you start a visit to the buildings, you have to go all the way through to the end to exit, which might be a fair trek given the size of the place! Those with mobility problems keep that in mind. Entrance to the buildings and grounds costs 8€, but EU citizens can get free admission on Wednesdays if you show your passport or other EU ID. The opening times are 10am-5pm from Oct-March, and 10am-6pm from April-September. Closed on all Mondays. Guided tours run throughout the day. The quiet town of San Lorenzo where the site is located is also worth a wander around, and there are plenty of restaurants offering menus del día for lunch.
Getting there: there are cercanías trains which leave frequently for El Escorial from Atocha. Journey time is around one hour and costs around 6-7€ return. You can also take the frequent 661 or 664 buses from Moncloa interchange (metro L3 and L6). The jouney is also one hours and costs roughly the same as the train, although it does leave you nearer the monastery.
To learn more about El Escorial, we recommned taking a look at this page by Feel Madrid. It gives you a good background into its history as well as lots more photographs.