Nacimiento (Spanish pronunciation: [nasiˈmjento], English: Birth) is a Chilean city situated in the Bío Bío Province, Bío Bío Region, 550 km (342 mi) south of Santiago, and 104 km (65 mi) from the closest major city in the region, Concepción.It was first used as a fort for the Spanish army to advance and control the territory, and it was officially baptised on Christmas Eve of December of 1603 with the name of Nacimiento de Nuestro Señor (Nativity of Our Lord).