The Ciénaga Grande de Santa Marta is the largest of the swampy marshes located in Colombia between the Magdalena River and the Sierra Nevada de Santa Marta. It has an area of 4280 km² , belongs to the outer delta system of the Madgalena River, and is separated from the Caribbean Sea by a narrow, sandy artificial spit built in the 1950s. The marsh's large lagoon is connected to the Caribbean Sea via a narrow strait (the La Barra channel) located between the town of Pueblo Viejo and the city of Ciénaga.