The Puerta del Sol (“Gate of the Sun”) is one of the best known and busiest places in Madrid. This is the centre of the radial network of Spanish roads (Km 0). The Puerta del Sol originated as one of the gates in the city wall that surrounded Madrid in the 15th century. Outside the wall, medieval suburbs began to grow around the Christian Wall of the 12th century.
The name of the gate came from the rising sun which decorated the entry, since the gate was oriented to the east.In the middle of the Puerta del Sol is a large equestrian statue of King Carlos III, installed here in 1997.The King looks out on a beautiful 18th century red brick building, the Casa de Correos (The House of the Post Office). It was built between 1766 and 1768. In front of the Casa de Correos, on the pavement, is the “kilometer 0” plaque.