The Guadalquivir is the fifth longest river in the Iberian peninsula and the second longest river with its entire length in Spain. The Guadalquivir is 657 kilometers long and drains an area of about 58,000 square kilometers. It begins at Cañada de las Fuentes in the Cazorla mountain range (Jaén), passes through Córdoba and Seville and ends at the fishing village of Bonanza, in Sanlúcar de Barrameda, flowing into the Gulf of Cádiz, in the Atlantic Ocean. The marshy lowlands at the river's end are known as "Las Marismas". It borders Doñana National Park reserve.(wikipedia)