La plaza Mayor is the heart of Madrid.
It used to be right at the outskirt of the old city, when the Muslims ruled it. There was then damps at its location, possibly a river. When the city expanded, it became 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 s know it today dates from 1790, as modeled by the architect Juan de Villanueva.