La plaza Mayor is the heart of Madrid.
Its location was right at the outskirt of the old city (Mayrit), when the Muslims ruled it. There was then damps, possibly a river. When the city expanded, it became a market and then the Plaza del Arrabal, which was a popular spot, both messy and unsanitary. Felipe II asked for its reform (in 1577). The construction started only under Felipe III's reign (in 1617). The Plaza Mayor as it is known today dates from 1790, as modeled by the architect Juan de Villanueva.
Aerial views (credits unknown).
Vintage (credits unknown).