Argentina (on right side of picture) and Uruguay (on left side) are the two countries which border the Río de la Plata. While some geographers consider it to be a gulf or marine sea, for those that consider it a river, it is the widest in the world, measuring 140 miles at its mouth. The capital cities of Buenos Aires and Montevideo can also be seen above on the right and far left sides of the river, respectively.
The river is an estuary where salt water mixes with freshwater. In this picture you can see the darker freshwater current flowing from inland rivers towards the Atlantic Ocean.
Besides many species of fish, the Río de la Plata is home to three species of sea turtles and the only species of river dolphin which can live in saltwater: the La Plata Dolphin. It also has the longest beak (relative to its body size) of any cetacean. To see a picture of a baby dolphin which was rescued in Uruguay, click here.
