Puerta del Sol sits at the centre of the radial network of Spanish roads, making it the literal zero point from which distances across the country are measured. A small plaque embedded in the pavement on the south side of the square marks Kilómetro Cero — worth finding if you enjoy the kind of geographical footnote that puts an entire nation beneath your feet. The square is free to enter at all hours, which makes it equally suited to a rushed ten-minute stop or a long people-watching session over a coffee from one of the nearby cafés.
The name translates as "Gate of the Sun", recalling a medieval city gate that once stood here and was decorated with a sun motif. Today the space functions as one of Madrid's principal transit hubs, connecting metro lines and bus routes that reach every corner of the city. Its central position in the Centro neighbourhood means that the Prado Museum, the Royal Palace, and the Gran Vía are all within comfortable walking distance, making Puerta del Sol a natural starting point for a day of exploring the capital on foot.