Built by King Philip II in the late 1500s as a monastery, palace, mausoleum and library all at once, El Escorial is one of the most historically significant royal sites in Europe.
Cercanías commuter trains run from Madrid's Atocha or Chamartín stations to El Escorial town in around an hour, with a short uphill walk or local bus to the monastery itself. It's the most budget-friendly of Madrid's classic day trips, needing only a standard commuter rail ticket.
The scale is the point — this is one of the largest Renaissance buildings in the world, built in a deliberately austere style that reflects Philip II's own severe reputation. The Royal Pantheon, where most Spanish monarchs since Charles I are buried, the library with its extraordinary ceiling frescoes, and the royal apartments are the highlights.
Around 2–3 hours for the complex itself, plus travel time — this makes for a fuller day trip than Segovia, closer in scale to Toledo.
The Valle de los Caídos (Valley of the Fallen) memorial is a short drive from El Escorial and sometimes combined into the same day by visitors with a car or organised tour — though it remains a genuinely contested historical site, tied to the Spanish Civil War, worth researching before you go.