 Located on the Príncipe Pío near the former Royal Palace of Madrid to the west of the central city, the Montaña barracks had been built in 1860.It consisted of three separate buildings joined together to make up a large fortress-like structure, fronted by a wide glacis and parapets.It was normally garrisoned by three regiments of infantry, a regiment of engineers and additional specialist units, although in July 1936 many of the soldiers were on summer leave.