Start at Puerta del Sol, the city’s energetic central square, and look for the famous Kilometer Zero plaque set into the pavement outside the Real Casa de Correos—the point from which Spain’s main roads are measured. Allow about 30 minutes for photos and a first feel for Madrid’s rhythm. From here, walk west along Calle Mayor for roughly five minutes to Plaza Mayor. Take a slow circuit beneath its arcades, then wander briefly through the nearby lanes; the square is at its most pleasant before the afternoon heat, though much of the surrounding area is shaded.
Continue on foot for another five minutes to Mercado de San Miguel for lunch. This elegant covered market is a convenient, atmospheric stop, with small portions of seafood, croquettes, cured meats, pastries, and vermouth. Expect around €20–35 per person if you try several stalls; seating fills quickly, so go slightly before peak lunch hours. It is generally open from late morning until late evening, but individual vendors may vary, and August schedules can change, so check the market’s official site that day.
After lunch, walk north toward the Royal Palace of Madrid, around 10 minutes via Calle de Bailén, or take Metro Line 2 from Sol to Ópera and walk the final few minutes. Reserve a timed entry in advance if possible, especially in August; allow 1½–2 hours for the grand state rooms, royal collections, and ceremonial spaces. Standard admission is usually roughly €12–14, with reduced rates available. The palace can be warm and busy, so keep water with you and avoid carrying large bags. When you finish, cross the street to Almudena Cathedral for about 45 minutes. Its modern interior, colorful ceiling, neo-Gothic exterior, and broad dome make a striking contrast with the palace. Entry to the cathedral is generally free with a donation requested; access to the dome or museum may require a separate ticket and may have limited hours.
End at Café de Oriente, directly across from the palace on Plaza de Oriente. It is a polished choice for dinner or simply coffee and a dessert, with one of the best evening outlooks toward the palace gardens. Budget about €25–45 per person, and book ahead for dinner or request terrace seating if the weather is comfortable. Madrid eats late, so arriving around 8:00 p.m. is relaxed; after dinner, take a short stroll around the illuminated Plaza de Oriente before returning by Metro from Ópera or walking back toward Sol.