The Walls del Arrabal (walls of the suburb) were the third in a set of five walls built around Madrid, now the capital of Spain. There are no remaining ruins of the Walls del Arrabal, leaving some debate as to their extent and the period of their construction. It is possible that the walls were built as early as the 12th century, however they were most likely constructed in 1438. The walls may have been intended to protect people against the plagues that ravaged the city at the time. The walls united the urbanized suburbs of the city and prevented entry of the infected.