Grijalva River
In Tabasco, the Grijalva River flows into the Usumacinta River. This confluence is at Tres Brazos, Centla, and it forms a large wetland region known as the Wetlands of Centla. The Wetlands of Centla is also the name of a biosphere reserve in the area; it contains , which makes it the largest protected wetland region in North and Central America and one of the top 15 wetlands (by size) in the world.