As you proceed upstream on Río Zaña, you will go through a lush tropical forest out of which emerge the ruins of an old colonial city, founded in 1563 by the Spanish. Ransacked by pirates in the late 17C, Zaña was little by little deserted before being totally wiped out after a terrible flood in 1720. Today, you can wander round the ruins of this dead city, dotted with the silent abandoned remains of churches, convents, streets and squares.