Everything starts at the Puerta del Sol: not just all Spanish roads but also the uprising the people of Madrid against the occupying French forces on May 2, 1808, as immortalised by Goya (visible in the Prado), which marks the beginning of the Spanish war of independence. The painting Dos de Mayo called in English The Second of May 1808 or The Charge of the Mamelukes forms a diptych with The Third of May 1808, which describes the execution of insurgents by the French troops.
Now closed to traffic, Puerta del Sol lost the sundial that gave it its name but retains the famous neon sign for Tio Pepe sherry and the giant sculpture by Antonio Navarro Santafe (1906-1983). It also remains a historic meeting place, where people gather to protest for democracy. It's also the ideal place to commence your perambulations through the narrow, winding streets of the old town.