The Puerta del Sol ("Gate of the Sun") is one of the best known and busiest places in Madrid. This is the centre (Km 0) of the radial network of Spanish roads. The square also contains the famous clock whose bells mark the traditional eating of the Twelve Grapes and the beginning of a new year. The New Year's celebration has been broadcast live on TV since 31 December 1962.
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.
Between the 17th and 19th centuries, the area was an important meeting place: as the goal for the couriers coming from abroad and other parts of Spain to the Post Office, it was visited by those eager for the latest news. The stairs to the Saint Philip church at the square were known as the Gradas de San Felipe, and were among the most prolific mentideros de la Corte (approx. trans. would be " lie-spreaders of the Court"). The House of the Post Office was built by French Architect Jacques Marquet between 1766 and 1768. The building was the headquarters of the Ministry of Interior and State Security during the Francisco Franco dictatorship. It is currently the seat of the Presidency of the Madrid Community.
The Puerta del Sol contains a number of well known sights associated both domestically and internationally with Spain. On the south side, the old Post Office serves as the office of the President of Madrid, the head of the regional government of the Autonomous Community of Madrid (not to be confused with the Madrid City Council, which is housed elsewhere). Also on its south side, the square holds a mounted statue of Charles III of Spain, nicknamed "el rey alcalde" ("the mayor-king") due to the extensive public works programme he set in motion. The famous Tío Pepe lighted sign is above the square's eastern building between the Calle de Alcalá and the Carrera de San Jerónimo. On the east side lies a statue of a bear and a madrone tree ( madroño ), the heraldic symbol of Madrid. Until 2009, the statue stood on the north side at the entrance to Calle del Carmen. The Mariblanca (actually Venus) marks the place of a former fountain.
The kilómetro cero is a plaque on the ground directly north of the Post Office serving as the symbolic centre of Spain. In addition to signalling the basis of numbering in the Spanish road system, the symbolic nature of the plaza ensures that it is the site of many rallies and protests, particularly against violence and war. Sol has seen protests against the terrorism perpetrated the March 11th attacks on commuter trains, and Spain's involvement in the Iraq War.
In 2011, the square has become established as a focal point and a symbol for the ongoing Spanish democracy demonstrations. The demonstrations included camping in the middle of the plaza initiated on May 15 amidst the election campaign for city halls and Autonomous Communities governments and fuelled up by Social media, particularly Twitter and Facebook. The demonstrations have then spread to many (more than 60) other cities in Spain. From 12 June remains in the square a free-standing domed structure pallets that fulfills the functions of information point 15-M Movement. This continues all the summer of 2011 until the dawn of August 2, when the national police decided to evict it. Currently dozens of committees have their assemblies in the iconic square.
The Puerta is located in the very heart of Madrid. Immediately to the southwest lies the Plaza Mayor; the Palacio Real, the official home of the Royal Family, is further west. Parliament and the museum district are to the east and the train station Atocha is to the southeast. Under the square lies a public transport hub served by lines 1, 2 and 3 of the Madrid Metro.