The Río Cauto forms a colorful delta as it empties and drops sediment into the Gulf of Guacanayabo in southeastern Cuba. Flowing for about 230 miles (370 km), the Cauto is Cuba’s longest river and one of only two navigable rivers in the country. Its delta is an internationally recognized wetland and is home to several species of mangrove, as well as the endangered Cuban parakeet and Cuban tree duck.