The Plaza Mayor is a major public space in the heart of Madrid, the capital of Spain. It was once the centre of Old Madrid,. It was first built during the reign of Philip III. Only a few blocks away is another famous plaza, the Puerta del Sol. The Plaza Mayor is for the people of Madrid and tourists to shop, walk around, eat, and enjoy the outdoors.

More details: https://en.wikipedia.org/wiki/Plaza_Mayor%2C_Madrid