Spain's former imperial capital, perched on a gorge above the Tagus River, is the single easiest great day trip from Madrid — and one of the best.
The AVE high-speed train from Madrid's Atocha station takes around 30 minutes — genuinely faster than getting across some larger cities. Regional trains and buses also run the route for less, taking closer to an hour.
Toledo's old town is compact and walkable, packed into its walled hilltop — the Cathedral (one of Spain's finest Gothic buildings), the Alcázar fortress, and the city's remarkable trio of surviving synagogues and mosque-turned-churches, a legacy of centuries when Christian, Jewish and Muslim communities coexisted here. El Greco lived and painted in Toledo for most of his career; several of his works remain in the city's churches.
A day trip covers the highlights comfortably, especially with an early start. But Toledo empties of day-trippers by early evening, and the old town at night — lit, quiet, largely to yourself — is different enough to justify staying over if your schedule allows it.
Toledo's old town is steep and cobbled throughout — comfortable shoes matter more here than almost anywhere else on a Madrid itinerary.