Buenos Aires and Montevideo stand on opposite banks of which estuary?

Buenos Aires, the capital of Argentina, lies on the south-western shore of the Rio de la Plata, and Montevideo, the capital of Uruguay, lies on its north-eastern shore.

What is the Rio de la Plata?

It is a wide, funnel-shaped estuary formed where the Parana and Uruguay rivers meet and flow into the Atlantic Ocean.

It is about 290 km long and widens from about 2 km at its head to about 220 km at its mouth, making it one of the widest estuaries in the world.

It forms part of the border between Argentina and Uruguay.

Its waters are brown because of the large amount of silt brought by the Parana.

Origin of the name:

"Rio de la Plata" means "river of silver" in Spanish. Early Spanish explorers hoped it would lead them to the silver mountains of the interior. The English name "River Plate" comes from this. Argentina's name also comes from the Latin word for silver (argentum).

The Parana-Paraguay-Uruguay basin:

• The basin of the Rio de la Plata is the second largest river basin in South America, after the Amazon.
• It covers parts of Brazil, Argentina, Paraguay, Bolivia and Uruguay.

The Parana is the main river. The Itaipu Dam on the Parana (between Brazil and Paraguay) is one of the largest hydroelectric dams in the world.

The Iguazu Falls lie on the Iguazu river, a tributary of the Parana.

The Paraguay river flows past Asuncion, the capital of Paraguay.

Why not the other options?

• ✗The Orinoco flows through northern South America into the Atlantic, forming a large delta.
• ✗The Sao Francisco is a major river of eastern Brazil, flowing into the Atlantic.
• ✗The Paraguay river is a tributary of the Parana and flows past Asuncion, not Buenos Aires.