Burgos is a city in northern Spain by the river Arlanzón. Burgos is rich in ancient churches and convents and the three most interesting historic sites are the cathedral, with its chapel of the Condestables de Castilla, the monastery of Las Huelgas, and the monastery of Miraflores. The construction of Burgos cathedral was ordered by King Ferdinand III and started  in 1221 and continued until 1765. It contains the tomb of Rodrigo Díaz de Vivar (1043-1099), known as El Cid Campeador, and his wife Doña Jimena.  The cathedral is a masterwork of Gothic Architecture and in 1984, Burgos Cathedral was designated a World Heritage Site by UNESCO.