 Complete the following phrase:  The Puerta del Sol contains a number of well known sights both domestically and internationally associated with Spain. On the south side, the old Post Office now 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 in the Palacio de Cibeles. There are two commemorative plaques in the front of the Royal House of the Post Office: one is devoted to the neighbours of Madrid who 