Puerta del Sol
Time Out says
It's the epicentre of Madrid and kilometre zero for all roads in Spain. In the 16th century, the Puerta del Sol was one of the acces points from outside the town. It got its name because of how the rising sun shone on the eastward-facing entrance. Conceived as a widening passage with a constant flow of people in transit, it soon became home to small traders who tried to do business among the comings and goings of the townspeople.
A lot of buildings went up back then that haven't survived the passage of time or have been toppled, such as the Buen Suceso church, and the convents of San Felipe el Real and Nuestra Señora de las Victorias. Currently, the most important building in the area is the Casa de Correos, seat of the government of the Community of Madrid.
The square is also home to one of the most famous statues in the city, 'El Oso y el Madroño' (The bear and the Strawberry Tree), which measures 4 metres high, weighs 20 tonnes and is always surrounded by groups of tourists taking photos of the symbol of Madrid.