Río de la Plata << `ree` oh duh luh PLAHT uh >> is an estuary, or funnel-shaped bay, on the southeastern coast of South America between Argentina and Uruguay. It is formed by the Paraná and the Uruguay rivers. The bay extends northwest from the Atlantic Ocean for about 170 miles (270 kilometers). A great volume of water flows into the bay from the rivers, and there is a powerful current. Many dangerous shallows make sailing risky. The natural harbor of Montevideo, in Uruguay, lies near the bay’s mouth, which is 140 miles (225 kilometers) wide. On the Argentine side, at Buenos Aires and La Plata, huge docks have been built and deep channels have been dredged.
In 1516, Juan Díaz de Solís became the first European to enter the bay. The Italian navigator Sebastian Cabot named the estuary Río de la Plata (Silver River). He probably chose this name because the local American Indians wore silver ornaments.
