The geographical and emotional centre of Madrid, radiating outward from the Puerta del Sol — the 0 km marker from which all Spanish roads are measured. The area encompasses the main shopping streets of Calle Preciados and Calle del Carmen, the grand colonnaded expanse of Plaza Mayor, and the maze of narrow streets between them full of old cafés, traditional shops, and the kind of tourist density that is worth pushing through to reach the good stuff underneath.
The historic core rewards careful navigation. Calle Mayor runs from Sol to the Royal Palace through layers of Habsburg-era architecture. Chocolatería San Ginés, open since 1894, operates nearly around the clock; the queue for churros and chocolate is always worth it after midnight. The Mercado de San Miguel on the western edge of Plaza Mayor is an upscale covered market best visited for a standing lunch rather than a sit-down meal.