La Plata Rio De
La Plata, Rio De, the name given to the combined mouths of the Uruguay and Parana rivers. It is about 200 miles long and 140 miles wide in the broadest part. There are wide sandbanks along the southern shore, and the only good harbour is that of Monte Video on the Uruguay coast. The water is remarkable for its muddy yellow colour. The Rio de la Plata was discovered by Diaz de Solis early in the 16th century; the discoverer was captured and eaten by cannibals.